Deepak Cyril D'Souza - US grants

APPLICANT'S ABSTRACT: Background and Objectives Schizophrenic have 3-4 fold higher prevalence rates of ethanol abuse disorders than the general population. Comorbid ethanol use/abuse has a significant negative impact on the course and treatment of schizophrenia. The existing literature about ethanol effects in schizophrenics is limited by its exclusive reliance on post-hoc reports of subjective drug effects; while ethanol's effects on positive and negative symptoms of schizophrenia remain unclear, ethanol may reduce anxiety, dysphoria and iatrogenic negative symptoms in schizophrenics. Our pilot data suggests that ethanol may reduce positive symptoms and increase negative symptoms in schizophrenics. In addition, ethanol appeared to have some dose and group-related differences. There are no pharmacological studies characterizing the effects of ethanol in schizophrenics. This proposal is the first prospective attempt to our knowledge, to study the acute dose-related behavioral, cognitive, and motor effects of ethanol in schizophrenics. This study is intended as a first in a series of studies exploring the problem of ethanol and schizophrenia. Research Plan and Methodology: Stable, neuroleptic-treated schizophrenics without previous ethanol abuse disorder will be compared to age, sex and education matched healthy controls. A comparison group of healthy controls is included because ethanol's mechanism of action suggests that it has unique effects in schizophrenics. Subjects will be studied under three conditions (placebo, low blood alcohol level - 0.002-0.004%, and high blood alcohol condition - 0.06-0.08%), in a double-blind, randomized, counterbalanced design. The primary outcome measures include: 1) 4 key positive and 3 key negative symptom subscales, of the Brief Psychiatric Rating Scale (BARS) 2) tests sensitive to frontal and temporal cortical function: Continuous Performance Test and the Hopkins Verbal Learning Test. Secondary outcome measures will include: 1) Biphasic Alcohol Effects Scale, 2) Visual Analog Scale for Mood States, 3) The simpson Angus Scale for Parkinsonism, 4) Barnes Akathisia scale, and 5) other cognitive tests. BARS data in schizophrenics will be analyzed using a repeated measures ANOVA with, within subjects factors for time for time and ethanol dose. Data from the biphasic Alcohol Effects Scale and cognitive tests will be initially analyzed using a repeated measures ANOVA with within subjects factors of ethanol dose and time, and a between subjects factors for diagnosis. For differences between patients and controls (cognitive test performance, blood alcohol levels, etc.,), relevant data will be added into the analysis as covariates. Post-hoc testing of peak changes from baseline will be conducted if there are significant time effects in the analysis using Dunnett's multiple t-tests. Results from this study will be used to guide the development of further, more comprehensive studies comparing alcohol abusing vs. Non-abusing schizophrenics and studying neurobiological correlates.

DESCRIPTION: (Adapted from applicant's abstract): Background: Based on the NMDA deficit hypothesis of schizophrenia, it has been proposed that facilitation of NMDA receptor function may have therapeutic potential in schizophrenia. Agonists of the strychnine-insensitive NMDA receptor glycine site offer a safe method to facilitate NMDA receptor function. Clinical trials with glycine added to neuroleptics show promise in the treatment of negative symptoms and cognitive deficits associated with schizophrenia. However, there are limitations to the interpretation of clinical trials. Further, clinical trials do not offer insight into the mechanism of action of glycine' therapeutic efficacy. The noncompetitive NMDA receptor antagonist ketamine, induces symptoms in healthy individuals resembling several aspects of schizophrenia. Preclinical studies suggest that glycine site agonists reverse the effects of non-competitive NMDA receptor antagonists. The ketamine paradigm offers a safe, feasible and clearly interpretable method to clarify the therapeutic potential of glycine and provide insight into the mechanistic underpinnings of its clinical efficacy. Aims: Does glycine pretreatment reduce ketamine-induced: 1) the perceptual alterations, 2) negative symptoms and 3) amnestic effects in healthy subjects. A secondary exploratory aim is to determine whether the effects of glycine are dose-related. Methods: Healthy subjects (n = 42) will complete 6 test days during which they will be administered intravenous glycine (0.1 g/kg), (0.2 g/kg) or placebo (normal saline) pretreatment followed by ketamine or placebo in a randomized, double-blind, counterbalanced order. Behavioral ratings for perceptual alterations (Clinician Administered Dissociative Symptom Scale), negative and positive symptoms of psychosis (Brief Psychiatric Rating Scale), recall (Hopkins Verbal Learning Test) and working memory will be administered. Ketamine levels will also be measured. Behavioral measures and drug levels will be subjected to a repeated measures analysis of variance (RMANOVA) with within subject factors of ketamine (ketamine vs. placebo), glycine (glycine vs. placebo), and time. Cognitive measures (HVLT, working memory) that are administered only once per test day, the RMANOVA performed on these data will just include within subjects factors of ketamine and glycine. Relevant covariates including age, weight, baseline WAIS-R scores, education level, drug levels will be included into the analyses. Pilot Data: Ketamine induces a schizophrenia-like syndrome in healthy humans that includes perceptual alterations, negative symptoms and amnestic effects have previously been reported. The central bioavailability and dose-related effects of intravenous glycine in healthy subjects will also be studied. Pilot data (n=12) towards this proposal suggests that glycine reduces ketamine-induced perceptual alterations, negative symptoms and impairments on recall without worsening positive symptoms.

DESCRIPTION (Adapted from Applicant's Abstract): Comorbid cannabis abuse has a significant negative impact on the course and treatment of schizophrenia. Comorbid cannabis abuse is highly prevalent in schizophrenia and schizophrenics prefer cannabis to other illicit drugs. There are no pharmacological studies characterizing the effects of cannabis in schizophrenics. The existing literature is limited by its exclusive reliance on naturalistic, retrospective self-report studies. These studies suggest that cannabis may reduce certain symptoms associated with schizophrenia at the expense of worsening others. Studying the effects of cannabis on the symptoms of schizophrenia is the first step in understanding the problem of cannabis abuse and schizophrenia. Cannabis continues to be a public health problem in the general population. While an association between cannabis use and psychosis in "healthy" individuals has been reported, the magnitude of cannabis' psychogenic effects has not been adequately studied using standardized assessments. This investigation proposes to answer the following questions: 1. Does THC have anxiolytic and euphoric effects in schizophrenia? 2. Is there altered cannabinoid sensitivity in schizophrenia: does THC increase psychosis and cognitive deficits in schizophrenics, is THC psychogenic in controls and finally, are schizophrenics more vulnerable to the effects of THC? Study subjects will be stable schizophrenics with previous cannabis exposure and matched controls. They will be tested under three conditions: placebo, 2.5 and 5mg THC delivered IV. Primary outcome measures are: PANSS, Visual Analogue Scale for Mood Disorders, CADSS (perceptual alteration scale) and tests sensitive to frontal and temporal cortical function. Secondary measures include measures of drug liking, movement rating scales and long term follow-up assessment of cannabis use.

[unreadable] DESCRIPTION (provided by applicant): Background: A family history of alcoholism is a risk factor for the development of alcohol problems. Factors that modulate the positive and negative reward valence of alcohol effects may influence the likelihood of repeated and or problematic use, and are therefore of interest. Alcohol has multiple targets in the brain that independently contribute to its behavioral effects. Studies with various pharmacological probes including alcohol, ketamine and benzodiazepines suggest differences between healthy individuals with a family history positive (FHP) or negative (FHN) for alcoholism. There is growing preclinical evidence suggesting involvement of brain cannabinoid receptor (CB-1R) function in the pharmacological actions of alcohol and in alcohol-drinking behaviors. Cannabinoids and alcohol activate the same reward pathways. CB-1R agonists stimulate while CB-1R antagonists suppress, alcohol self-administration and the motivational properties of alcohol. Comparison to wild type mice, CB-1R knockout mice show 1) significantly lower levels of alcohol preference and consumption, 2) slower rate of acquisition of alcohol drinking behavior, 3) lower alcohol sensitivity, and 4) blunted alcohol-induced dopamine release in the nucleus accumbens. Finally, alcohol preferring mice have a significantly lower level of CB-1R binding sites and higher affinity for CB-1R agonist than alcohol-avoiding mice. Despite these preclinical data, there is a paucity of clinical research in this area. [unreadable] [unreadable] Hypotheses: Individuals with a family history of alcoholism (FHP) will exhibit blunted 1) euphoric, 2) perceptual and 3) amnestic effects in response to ?-9-tetrahydrocannabinol (?9-THC) administration compared to individuals without a family history of alcoholism (FHN). [unreadable] [unreadable] Methods: An equal number (n=18) of healthy FHN and FHP will complete 3 test days separated by a week during which they will receive intravenous ?9-THC (0, 0.018 and 0.036 mg/kg) over 20 minutes in randomized, counterbalanced fashion under double-blind conditions. Primary outcome variables include measures of euphoria, perceptual alterations and delayed recall. [unreadable] [unreadable] Preliminary Results: FHP individuals (n=4) showed blunted responses to the effects of ?9-THC on euphoria, perceptual alterations and delayed recall relative to FHN controls. These results may reflect indirect evidence of altered CB-1R function in FHP individuals. [unreadable] [unreadable] [unreadable]

[unreadable] DESCRIPTION (provided by applicant): Cannabis one of the most commonly used and abused illicit substances may produce harmful effects in some individuals. In laboratory studies, we have shown that Delta-9-tetrahydrocannabinol (d-9rTHC) induced transient but clinically significant psychotomimetic and amnestic effects in some but not all carefully screened healthy individuals. Epidemiological data suggest that cannabis is a modest risk for the emergence of psychosis and psychotic disorders. Further, a recent report suggests that polymorphisms of the gene for the enzyme catechol-O-methyltransferase (COMT) might moderate the risk of psychosis following cannabis exposure. COMT Val108/58Met polymorphism moderates executive function and the physiology of the prefrontal cortex in humans and is indirectly associated with increased mesolimbic dopamine transmission. Cannabinoids have been shown to increase dopaminergic transmission both in the prefrontal cortex and striatum, and these effects might contribute to the psychotomimetic and amnestic effects of cannabinoids. Similarly, hippocampal GABAergic systems may contribute to the psychotomimetic and amnestic effects of cannabinoids. Hypotheses: Polymorphisms of the genes for COMT and GABRA2 moderate the psychotomimetic and amnestic response to d-9-THC. Methods: 81 healthy subjects (27 each of val-val, val-met and met-met genotype) will complete 2 test days during which they will receive d-9-THC (placebo or 2.5 mg) intravenously over 20 minutes in randomized counterbalanced fashion under double-blind conditions. Primary outcomes include psychotomimetic effects (PANSS positive symptoms subscale) and total immediate recall and delayed free deficits (Rey Auditory Verbal Learning Test) will be measured. Secondary outcomes include measures of spatial working memory, delayed recognition memory and attention. Results: Pilot data (n=15) show that otherwise healthy individuals homozygous for 1) the COMT Val108/58Met allele (Val-Val) and 2) the "tt" genotype of a SNP marker (rs279858) of the GABRA2 gene, are more vulnerable to experience clinically significant psychotomimetic and amnestic effects induced by d-9-THC. [unreadable] [unreadable] [unreadable]

[unreadable] DESCRIPTION (provided by applicant): Background: The mechanisms by which cannabinoids produce transient psychotomimetic effects and impairments in attention and memory are not clear. Perceptual, memory and attentional functions are based on distributed processes that are believed to be "bound" together by synchronous high frequency oscillatory activity. In humans, macroscopic neural synchrony can be evaluated non-invasively by entrainment of the EEG to sensory (auditory) stimuli presented of various frequencies. The brain acts as a tuned oscillator, and the steady-state EEG waveform entrains to the frequency and phase of the presented stimulus, providing an indicator of the functioning state of the neural circuits supporting synchrony. Cannabinoids decrease gamma band power in rat hippocampal slices and cannabis users show reduced power in the beta band relative to controls during an auditory entrainment paradigm. We are unaware of any studies examining the acute effects of cannabinoids on EEG neural synchrony in healthy humans. Hypothesis: ?9-THC, in a dose-related manner, will reduce spectral power of the EEG response to an auditory steady state entrainment at 20, 30 and 40 Hz. Secondary analyses will examine the effects of ?9-THC on specific features of the steady state EEG response that may contribute to spectral power reductions including event spectral perturbations (ERSP) and inter-trial phase coherence (ITC). Changes in perceptual alterations, psychotic-like symptoms, and cognitive impairments (attention, verbal recall and working memory) induced by ?9-THC will correlate with changes in spectral power. Methods: Carefully screened healthy individuals will complete 3 test days during which they will receive (0, 0.015, 0.03 mg/kg) ?9-THC in a double-blind, randomized, counterbalanced design. Indices of neural synchrony will be assessed by measurement of EEG spectral power evoked by presentation of auditory click trains at 20, 30 and 40 Hz. Perceptual alterations, psychotic-like symptoms, sustained attention, immediate verbal recall, spatial working memory and visual object recognition memory will also be assessed. Preliminary results: ?9-THC produced a dose-related reduction in power at 30 HZ in response to 30 Hz auditory stimulation (driving). ?9-THC also reduced event related spectral perturbation to 20 and 30 Hz driving. ?9-THC reduced intertrial coherence to 40 Hz driving and to a lesser extent 20 and 30 Hz driving. In a dose- related manner, ?9-THC increased scores on measures of perceptual alterations and psychosis, and induced impairments in measures of verbal recall, spatial working memory, visual recognition memory and attention. Relevance: The aim of this project is to characterize the effects of cannabinoids on electrical communication within the brain (neural synchrony) using EEG in healthy humans and to relate these effects to their behavioral and cognitive effects. [unreadable] [unreadable] [unreadable] [unreadable]

DESCRIPTION (provided by applicant): GABA Deficits and Vulnerability to Cannabinoid-Induced Psychosis Cannabinoids (CBs) induce transient psychotic symptoms and cognitive dysfunction in healthy individuals and exacerbate symptoms in schizophrenia patients. However, the latter are more vulnerable to the effects of cannabinoids. The enhanced cannabinoid sensitivity in schizophrenia might be driven by the well documented gamma-amino butyric acid (GABA) receptor deficits in schizophrenia. Converging preclinical evidence suggests important interactions between CB and GABA systems. CB1 receptors (CB1-Rs) are present on the axon terminals of cholecystokinin (CCK) containing GABA neurons that target pyramidal cells. These GABA neurons orchestrate the synchronization of neural activity which is believed to play an important rolein perceptual, memory and attentional processes. Activation of CB1-Rs on the axon terminals of CCK containing GABA neurons reduces GABA release, resulting in disinhibition of pyramidal cell activity. If this were to occur in the presence of a GABA deficit, as might be the case in schizophrenia, this could lead to further disinhibition and desynchronization of pyramidal cell activity, leading to perturbation of gating and associative functions, culminating in psychotic symptoms. Hypothesis: If GABA deficits increase the vulnerability of schizophrenic patients to the effects of cannabinoids, then inducing a GABA deficit in healthy subjects will potentiate the psychotomimetic, amnestic and neural synchrony deficits produced by ?9-THC. We have shown that in healthy individuals 1) ?9-THC induces transient psychosis and memory impairments, 2) both acute and chronic exposure to cannabinoids is associated with alterations in neural synchrony, and 3) GABA deficits produced by iomazenil, enhanced the psychotomimetic effects of a serotonergic agent. Methods: Healthy subjects will complete 4 test days during which they will receive intravenous iomazenil or placebo pretreatment, followed by intravenous ?9-THC or placebo, in a double-blind, randomized, counterbalanced design. Perceptual alterations, psychotic-like symptoms and memory will be assessed. Indices of neural synchrony will be assessed by measurement of EEG spectral power evoked by presentation of auditory click trains at 20, 30 and 40 Hz. PUBLIC HEALTH RELEVANCE: The aim of this project is to evaluate whether a reduction in the principal inhibitory chemical messenger system in the brain, the GABA receptor system, enhances the vulnerability to the psychotomimetic effects of THC, the main active component of cannabis.

DESCRIPTION (provided by applicant): Nicotinic Acetylcholine Receptors in Schizophrenia Schizophrenic patients have among the highest rates of tobacco smoking and nicotine is thought to alleviate some of the symptoms associated with schizophrenia. Chronic nicotine exposure up regulates nicotinic agonist binding to brain nicotinic acetyl choline receptors (nAChR). In postmortem studies, there are region-specific increases in high affinity nAChR binding in healthy human tobacco smokers but not in schizophrenic smokers. While these data suggest high affinity nAChR dysregulation in schizophrenic smokers, there are no in vivo data showing nAChR dysregulation in schizophrenia or how it might relate to smoking or the symptoms (cognitive deficits) associated with schizophrenia. Using [123I]5-IA-85380 (5-IA) and SPECT imaging we have recently shown that consistent with post mortem data, healthy smokers have 30% higher 22-nAChR availability vs. never smokers. Consistent with post-mortem studies in our pilot data schizophrenic smokers (SS) (n=7;6 medicated and 1 unmedicated) show region specific reductions in brain [123I]5-IA uptake relative to healthy smokers (HS) regardless of medication status. These findings may reflect a failure to upregulate 22-nAChR in schizophrenic smokers. Further, SS show higher [123I]5-IA uptake compared to healthy never smokers (HNS) while schizophrenic nonsmokers (SNS) (n=4) show lower [123I]5-IA uptake in the thalamus, but also in the parietal, frontal, and occipital cortices compared to HNS. Memory and attention were disrupted by smoking abstinence and restored by the resumption of smoking. Aims: Using SPECT and 5-IA, this proposal aims to determine if 1A) SS show reduced region specific 22- nAChR availability relative to HS;1B) unmedicated SS show reduced region specific 22-nAChR availability relative to HNS;1C) there are differences in 22-nAChR availability between medicated and unmedicated SS;2) SNS show lower 22-nAChR availability compared to HNS. In addition we plan to explore 1) differences in regional 22 nAChR availability between medicated SS vs. medicated SNS;2) the relationship between cognitive test performance and regional 22-nAChR availability;and 3) the effects of smoking abstinence and smoking resumption on cognitive test performance. Methods: HS and SS (medicated and unmedicated) will achieve 5 days of confirmed abstinence with a combined strategy of counseling and contingency management, and hospitalization for only the schizophrenic smokers. Matched HNS and SNS will also be studied. All subjects will be studied using SPECT and 5-IA followed by an MRI for coregistration. Cognitive testing (verbal memory, attention, working memory and selective attention) will be assessed while smoking as usual, 24 hours after quitting, 5 days abstinence and if subjects resume smoking. Cognitive data will be correlated with regional brain [123I]5-IA uptake (VT and VT'). PUBLIC HEALTH RELEVANCE There are high rates of smoking in individuals with schizophrenia and smoking (nicotine) may alleviate certain symptoms of schizophrenia. This has led to the suggestion that alterations in the nicotine receptor system may contribute to the high rates of smoking (addiction) in schizophrenia and some of its symptoms. This grant application proposes to use brain imaging to study the nicotine receptor system in schizophrenia.

DESCRIPTION (provided by applicant): Cannabis is the most commonly used illicit drug worldwide. There is increasing recognition of a cannabis dependence syndrome that includes both tolerance and withdrawal. Furthermore, the rates of cannabis use have increased during early adolescence, when the developing brain might be especially susceptible to environmental exposures. This public health concern is further fueled by the fact that the potency of cannabis seems to have increased over the past decades. There is also increasing demand for treatments for cannabis use disorders. Therefore, it is important to fully understand the consequences of cannabis dependence in humans on the brain cannabinoid system. Exogenous cannabinoids produce their psychoactive effects via the activation of brain CB1 receptors (CB1R). Repeated exposure to cannabis and CB1R agonists is associated with the development of tolerance and dependence. While this has been shown to be accompanied by CB1R downregulation in animals, it has yet to be demonstrated in humans, in vivo. The discontinuation of chronic, heavy exposure to cannabinoids in both humans and animals, and the administration of CB1R antagonists to cannabinoid dependent animals, is associated with a clear withdrawal syndrome. Finally, with prolonged abstinence there seems to be a reversal of tolerance, which in animals has been shown to be accompanied by normalization of CB1Rs. However, this has yet to be demonstrated in humans, either post mortem or in vivo. The aim of the current proposal is to use the validated CB1R PET ligand [11C]OMAR and High Resolution Research Tomography (HRRT) to measure CB1R availability in vivo in cannabis-dependent individuals at 1) baseline, 2) following brief (48 hours) confirmed inpatient abstinence (at the peak of cannabis withdrawal and CB1R downregulation), and 3) after prolonged (4 weeks) confirmed outpatient abstinence. It is expected that at baseline, cannabis-dependent subjects (n=8) will have lower CB1R availability than matched controls (n=8), but this difference will no longer be present after 4 weeks of abstinence. Furthermore, cannabis-dependent subjects will have lower CB1R availability during acute cannabis withdrawal relative to their baseline state. Taken together, it is hoped that data from this study will elucidate the neurobiological consequences of chronic cannabis consumption and its effect on CB1 receptors, and will shed new light on the status and function of CB1 receptors during active cannabis use, and withdrawal. PUBLIC HEALTH RELEVANCE: Little is known about the consequences of heavy cannabis use on the brain cannabinoid system. This grant application proposes to use brain imaging to study the changes in the brain cannabinoid receptor system as a result of heavy cannabis use, 2 days after stopping cannabis use and again after 4 weeks of abstinence from cannabis.

DESCRIPTION (provided by applicant): Cannabis contains a number of compounds including delta-9-Tetrahydrocannabinol (THC) and cannabidiol (CBD). THC, believed to be responsible for the psychotic effects of cannabis, produces a wide range of psychotomimetic, cognitive and psychophysiological effects in healthy humans that are relevant to schizophrenia. CBD, on the other hand, does not have any propsychotic effects and instead appears to reduce the overall psychotic effects of cannabis. While preclinical data support the antipsychotic potential of CBD in a number of animal models of psychosis, there are significant limitations to evidence from human studies. CBD attenuates a number of THC-induced subjective effects, whether this extends to THC-induced psychotomimetic or cognitive effects is unclear. Aims: The overarching aim of this proposal is to demonstrate that pretreatment with CBD will reduce a wide range of psychotomimetic, cognitive and psychophysiological effects induced by the acute administration of THC in healthy humans. This study is designed as a first proof of concept to explore the antipsychotic potential of CBD in healthy individuals. The data from this study will serve as a prelude to more comprehensive and expensive clinical trials of CBD in patients with schizophrenia. Methods: 20 psychiatrically and medically healthy individuals, who have been exposed to cannabis but have never met criteria for a cannabis use disorder, will be recruited from the community to participate in this randomized, double-blinded, placebo-controlled study. Subjects will be randomized to (A) four test days or (B) six test days. All 20 subjects will complete (A) 4 test days and receive either CBD (5mg) or placebo followed by THC or placebo intravenously. 10 subjects randomized to (B) six test days will participate in 2 extra test days during which they will receive CBD (2.5mg or 7.5mg) followed by THC. Subjects will be tested before and after drug administration for schizophrenia-like symptoms (measured on the positive and negative syndrome scale (PANSS) and clinician administered dissociative symptoms scale (CADSS), cognitive impairments (in verbal memory, spatial working memory and sustained attention), subjective effects (measured on a visual analog scale of mood states for anxiety and euphoria), psychophysiological effects (P300 event related potential) and endocrine effects (serum ACTH, cortisol and prolactin levels). In addition, blood levels of THC, its active and inactive metabolites, and CBD will be measured in each subject to explore pharmacokinetic interactions. Significance: Most pharmacological treatments currently available for schizophrenia involve primarily the dopaminergic and serotonergic systems. There is a need to develop new pharmacotherapies for schizophrenia driven by novel hypotheses. CBD targets the cannabinoid system and may have antipsychotic properties. Thus, exploration of its antipsychotic properties may lead to newer therapeutic options for schizophrenia.

DESCRIPTION (provided by applicant): Cannabis dependence is a well-recognized syndrome characterized by tolerance and withdrawal for which there are no approved treatments. Several medications have been tested for cannabis withdrawal and/or dependence, but none have been shown to be consistently effective. Substitution treatment with delta-9- tetrahydrocannabinol (THC), while showing some promise in reducing cannabis withdrawal syndrome (CWS), is limited by its psychoactive effects, abuse liability, and by its limited relapse prevention effects An alternative to substitution treatment may be to potentiate the signaling through the endogenous cannabinoid system. Anandamide, a principal endogenous ligand of brain cannabinoid receptors (CB1R) is degraded by the enzyme fatty acid amide hydrolase (FAAH). Recently, a FAAH inhibitor which increases anandamide levels was shown to reduce CWS in THC-dependent animals. Compared to THC or cannabis, FAAH-inhibitors 1) do not have psychoactive effects, 2) are not rewarding, 3) do not increase the abuse liability of other addictive drugs, 4) are not associated with tolerance and 5) produce fewer changes in CB1-R function. PF-04457845 is an orally active, long-acting, potent and selective FAAH inhibitor that does not have psychoactive or cognitive effects, does not have effects suggestive of abuse liability or discontinuation-related withdrawal symptoms and is well-tolerated at the proposed dose. Hypotheses: PF-04457845 will attenuate the subjective, behavioral, polysomnographic, cognitive and endocrine changes associated with cannabis withdrawal syndrome. Furthermore, PF-04457845 will reduce cravings for cannabis and relapse rates in recently abstinent cannabis dependent individuals. Approach: The effects of FAAH inhibition on cannabis withdrawal and relapse will be studied in this proof-of- concept study. Treatment seeking cannabis-dependent subjects (n= 48) with a clear history of CWS will be included in a randomized, double-blind, placebo-controlled study. After a screening period, subjects will be randomized to receive placebo or PF-04457845 (4 mg) provided through an agreement with Pfizer. The treatment phase consists of a 1-week inpatient stay to achieve abstinence and precipitate withdrawal, followed by a 3-week outpatient phase to assess relapse prevention. Innovation: There are no known treatments for cannabis dependence. FAAH inhibitors are a novel class of compounds. There are very few FAAH-inhibitors that are available for use in humans, and none are available commercially. FAAH-inhibitors have not been tested for the treatment of cannabis dependence in humans. Therefore, the proposed study is innovative.

DESCRIPTION (provided by applicant): Converging lines of evidence suggest a cannabinoid hypothesis of schizophrenia that includes exogenous and endogenous elements. According to the better know exogenous hypothesis, 1) cannabinoids can produce a full range of transient schizophrenia-like effects in healthy individuals, 2) cannabinoids can exacerbate psychotic symptoms, trigger relapses and negatively impact the course of illness in schizophrenia patients, and 3) exposure to cannabis may contribute to the risk of developing schizophrenia. Evidence supporting an endogenous hypothesis includes 1) the presence of elevated cerebrospinal fluid (CSF) endocannabinoid levels and 2) post-mortem findings of regional alterations in brain cannabinoid receptors (CB1R) in schizophrenia. Additionally, schizophrenia patients are also more vulnerable to the behavioral and cognitive effects of cannabinoids; a finding that may reflect abnormalities in the endocannabinoid system. The post mortem findings of CB1R availability have been mixed with some studies showing decreases, and others showing increases in different brain regions. Furthermore, the effects of antipsychotic medication on CB1R availability in schizophrenia are not clear, and the relationship between CB1R availability and behavioral and cognitive symptoms in schizophrenia has not been adequately studied. The recent development of several CB1R specific Positron Emission Tomography (PET) ligands, including [11C]OMAR, provide the tools to directly measure CB1R availability in schizophrenia in vivo. Hypothesis: Schizophrenia patients will have lower CB1R availability than controls. Furthermore, unmedicated schizophrenia patients will have lower CB1R availability relative to medicated (antipsychotic- treated) patients. Finally, in schizophreni patients, measures of memory and psychosis will correlate with CB1R availability in hippocampus and ventrostriatal regions, respectively. Aims: To compare CB1R availability in vivo in schizophrenia patients (including a subgroup of patients not taking antipsychotic medications), to age, gender, Body Mass Index (BMI), and smoking status matched healthy controls using the validated CB1R PET ligand [11C]OMAR and High Resolution Research Tomography (HRRT) PET. In schizophrenia subjects, measures of symptoms and cognition will be correlated to CB1R availability in relevant brain regions. Preliminary Results: We have developed appropriate methods for quantitative analysis of [11C]OMAR data and suggest that [11C]OMAR is an appropriate tracer with which to investigate the CB1R system in humans. Schizophrenia patients have decreased CB1R availability in several brain regions, with the greatest reductions in the pallidum > anterior cingulate cortex > putamen > hippocampus > amygdala. Since the findings were present in subjects who were unmedicated, the observed changes cannot be attributed to the effects of ongoing antipsychotic medications. PUBLIC HEALTH RELEVANCE: The brain cannabinoid receptor system may be altered in schizophrenia. We propose to image brain cannabinoid receptors (CB1R) in individuals with schizophrenia compared to controls. Furthermore, the effects of antipsychotic medications on CB1Rs, and the relationship between CB1Rs and measures of symptoms in individuals with schizophrenia will also be studied.

? DESCRIPTION (provided by applicant): Motor vehicle accidents (MVAs) are among the top 10 leading causes of morbidity and mortality worldwide (1). In 2012, within the United States (US) there were about 30,000 MVAs that resulted in 33,561 fatalities, in addition to 1,634,000 reported MVAs that caused injury (2). Alcohol and cannabis are very important contributors to both impaired driving and MVA's (3). While the effects of alcohol on driving are well- known and have been widely studied (4), the effects of cannabis or its constituent cannabinoids on driving are less clear (5), and there is even less known about the effects of the combination of alcohol and cannabinoids on driving. With the growing legalization of both recreational and medical use of cannabis, the growing perception, especially among young adults, that cannabis is safe (6), and the paucity of experimental data to inform public health policy regarding driving under the influence of both substances, there is a need to study the combined effects of cannabinoids and alcohol on driving. Hypothesis: The combination of modest recreational doses of THC and ethanol, will impair simulated driving, event related potentials (ERPs) relevant to driving, and driving related cognitive function to a greater extent than either drug individually. Methods: In a randomized, double-blind, placebo-controlled, crossover (2x2), counterbalanced laboratory study, healthy subjects (n=25) will simultaneously receive through separate intravenous (IV) lines 1) IV ethanol or placebo (saline) to reach a BrAC of 0.04% (equivalent to ~2 drinks over 1 hour) within 20 minutes and remain clamped at this level for an additional 60 minutes using a computer-assisted alcohol infusion system, and 2) IV THC (0.015 mg/kg = 1/4 - 1/2 cannabis joint) or placebo (saline) over 20 minutes. Subjects will complete 1) a day and night driving course on a driving simulator, while EEG is recorded to obtain the driving error related ERPs - ERN and Pe; 2) an EEG P300 novelty task, and 3) a battery (CogState) of cognitive tests relevant to driving. Supporting feasibility data: We have the experience and expertise, to administer IV ethanol (n>20) and THC (n>400), in addition to having the regulatory approvals (IND, Schedule 1 license) necessary to administer IV THC. We have demonstrated that IV ethanol increases SDLP on a simulated driving task, and have also shown the separate effects of both IV ethanol and IV THC on reducing amplitude of the P3a.

PROJECT SUMMARY AND ABSTRACT Background: Cannabis is the most commonly used illicit drug worldwide. The potency of cannabis has increased and so has the use of highly potent synthetic cannabinoids (`Spice'). Furthermore, the ?medical? and recreational use of cannabis is increasingly being legalized across the U.S. Therefore, it is important to understand the consequences of chronic cannabinoid exposure on the brain, including the consequences of these changes on neural function, and importantly if/how these evolve when cannabis use stops. Cannabinoid receptor (CB1R) availability can be measured in vivo using Positron Emission Tomography (PET). Neural oscillations, an index of information processing, are sensitive to the effects of CB1R activation and can be measured using electroencephalography (EEG). Hypotheses: Cannabis dependent subjects (CDs) will show lower CB1R availability at baseline relative to controls. CB1R availability will begin to normalize after 48 hours of abstinence (but not to HC levels) and will return to control levels after 4 weeks of abstinence. CDs will exhibit decreased ?- and ?-band neural oscillations compared to HCs at baseline, which will be most disrupted after 48 hours of abstinence and will return to control levels after 4 weeks of abstinence. Across the 3 time points, measures of ?- and ?-band oscillations will correlate with CB1R availability. Finally, CB1R availability, ?- and ?-band power, and coherence will correlate with performance on the cognitive tasks. Methods: The proposed study will utilize 1) CB1R PET ligand [11C]OMAR and High Resolution Research Tomography (HRRT) and 2) EEG to evaluate the temporal course of CB1R availability and neural oscillations, respectively, in cannabis-dependent individuals (n=25) at baseline (smoking cannabis as usual), following brief (48 hour) monitored inpatient abstinence (when cannabis withdrawal is most likely to occur), and after prolonged (4 weeks) monitored abstinence. Neurocognitive outcomes (e.g., verbal learning) which are known to be impaired by chronic cannabis exposure will also be assessed in order to relate the receptor and electrophysiological findings to domains germane to ?real world? functioning. A sample of healthy control individuals (n=12) will also be assessed at the same time points. This design will allow both within-subject and between-subject analyses across three time points.Taken together, it is hoped that data from this study will elucidate the neurobiological consequences of chronic cannabis consumption and its effect on CB1Rs, and will shed new light on the status and function of CB1Rs during active cannabis use, and withdrawal.

? DESCRIPTION (provided by applicant): Cannabinoids can induce psychotic episodes which are time-locked to exposure, outlast the duration of intoxication, and are clinically significant. CIAPP is distinct from 1) the link between adolescent cannabis exposure and later schizophrenia and 2) cannabinoid induced psychotic symptoms that do not persist beyond intoxication. This latter entity, that we refer to as cannabinoid induced acute persistent psychosis (CIAPP), is the focus of this exploratory study. The high rates and earlier onset of cannabis use, the increasing potency of cannabis, the legalization of medical and recreational cannabis use, the increasing availability and use of edible cannabinoid products, the recreational use of highly potent synthetic cannabinoids, and the high rates of emergency department visits related to cannabis, calls for the need to characterize CIAPP. Given the unpredictable occurrence of CIAPP, we propose using a nested, case-control approach that capitalizes on a unique, annually recurring phenomenon: the predictable and ritualistic use of cannabis by large numbers of people during certain festivals and ensuing cases of CIAPP. Every year, millions of people (representative of the general population) in Northern India celebrate certain festivals during which there is widespread use of cannabis. These festivals are followed by a spike in hospitalizations for psychosis at psychiatric facilities. Since these festivls occur at a predetermined time annually, a large number of CIAPP cases and controls can be studied in a planned manner. The proposed exploratory project capitalizes on 1) the predictable occurrence of CIAPP, 2) large numbers of cases (numbers that would be difficult to capture in the US at a single site), 3) a sample that is more representative of the general population than those who participate in laboratory studies, 4) the relative absence of the confounding effects of other drugs, and 5) hospitalization of cases that would permit detailed characterization. Hypotheses: Relative to controls, CIAPP cases will have higher scores on measures of positive and negative symptoms, worse cognitive deficits, and greater deficits in EEG indices of information processing (ASSR [lower ITC and spectral power], P300 [lower amplitude], P50 gating [altered gating ratios] and neural noise [higher LempelZivComplexity]). While most behavioral differences will resolve over time, some cognitive and psychophysiological differences will persist (trait), albeit of lower magnitude. Methods: Cases of CIAPP (n=71) will be compared to controls (n=71) (friends who consumed cannabis but did not develop psychosis). Demographic information, personal and family history of mental illness and drug use, psychosis (PANSS), and cognitive (Cogstate battery) and psychophysiological indices of information processing (P50, P300, ASSR and noise [LZC]) will be assessed 1) at admission (state), 2) around discharge (state and trait), and 3) again, within 6 months post discharge (trait). A long-term goal is to build on this exploratory study a longitudinal study (R01) of CIAPP, since it may portend a recurrent psychotic disorder.

ABSTRACT Background: Cannabis is one of the most widely used substances by children and young adults. While there is accumulating preclinical evidence that exposure to cannabinoids in adolescence has far reaching consequences on neurodevelopment, the effects of early cannabis exposure on the brain has not been adequately studied in humans. Thus, there is a need to assess the impact of cannabis exposure on the developing brain during adolescence using measures that are as proximal to brain function as possible. Oscillatory activity in the gamma (?) band (30-80 Hz) has been shown to be critically involved in brain functions such as attention, and working memory. There is compelling evidence that many features of ? oscillations evolve over childhood and adolescence following specific trajectories that coincide with critical milestones of brain development. The location and modulatory role of cannabinoid receptors type 1 (CB1R) make the endocannabinoid system well poised to influence ? oscillations. In fact, animal studies show that CB1R agonists acutely disrupt ? oscillations and that exposure to cannabinoids in early adolescence, but not adulthood, selectively disrupts ? oscillations measured later during adulthood . Thus, the study of the effect of cannabis on ? oscillations in adolescents has the potential to provide objective cross-sectional and longitudinal information about the effects of cannabis on the developing brain in real time at their inception. Hypothesis: The overarching hypothesis of this exploratory grant proposal is that cannabis-using adolescents (CAN+) will show reductions in evoked and induced ? oscillations as captured by electroencephalography (EEG), compared to cannabis-naïve adolescents (CAN-). Furthermore, the neurodevelopmental trajectory (i.e. increase over time) of evoked and induced ? oscillations will be blunted in CAN+. Reductions in evoked and induced ? oscillations are predicted to correlate with deficits in cognitive test performance and academic achievement in CAN+. Methods: In this part cross-sectional and part longitudinal prospective study, an equal number (n=34) of CAN+ and CAN- (13-16 years) will be assessed at baseline, 9 and 18 months. ? oscillations will be recorded with EEG while the subjects engage in two widely used, well-validated tasks to elicit evoked (steady-state response tasks) and induced (Gestalt perception tasks) ? activity. Cognition (CogState battery) and school grade data will be collected. Cross-sectional comparisons (CAN+ vs. CAN-) will be conducted at all time-points for all the measures. Longitudinal age-related changes of ? oscillations of CAN+ and CAN- will be compared across the 3 time points. Correlations between deficits in ? oscillations and both cognitive performance and academic achievement will be obtained.

ABSTRACT Cannabis use disorder (CUD) is a well-recognized syndrome characterized by tolerance and withdrawal. Repeated cannabis exposure is associated with downregulation and desensitization of the brain endocannabinoid (eCB) system. While several medications have been tested for CUD, none are U/S Food and Drug Administration (FDA) approved or clinically accepted. Substitution treatment while showing some promise in reducing the cannabis withdrawal syndrome (CWS), is limited by its psychoactive effects, abuse liability, and by its limited relapse prevention effects. In individuals with CUD, in vivo imaging studies have demonstrated: 1) lower brain cannabinoid receptors (CB1R) and 2) lower levels of the eCB-metabolizing enzyme fatty acid amide hydrolase (FAAH) which is responsible for degrading anandamide (AEA), a principal endogenous ligand of the cannabinoid system. Thus, an alternative to substitution treatment may be to potentiate signaling through the eCB system to restore eCB tone that is altered with chronic cannabis exposure. FAAH inhibitors which increase AEA levels reduce CWS in THC-dependent animals. PF-04457845 is an orally active, long- acting, potent, and selective FAAH inhibitor. In our completed proof of concept (POC), double-blind, randomized, placebo-controlled, inpatient/outpatient study relative to placebo, the FAAH inhibitor PF-04457845 (4mg QD) administered for 4 weeks reduced 1) cannabis withdrawal, 2) cannabis use, and 3) disturbances in sleep, in DSM-4 cannabis dependent individuals (n=60). PF-04457845 was very well-tolerated and was not rewarding/reinforcing. Hypotheses: PF-04457845 will reduce cannabis use, withdrawal symptoms, and sleep disturbances including time in Stage N3 sleep, in treatment-seeking individuals with a cannabis use disorder (CUD). Approach: The efficacy and safety of PF-04457845 (4 mg QD) on cannabis use will be studied in treatment- seeking male and female CUD subjects (n= 260 [including 25% attrition]) in a placebo-controlled, double-blind, randomized, multicenter, 12-week long (8 weeks of treatment & 4 weeks follow up) parallel-group study. Innovation: The proposed treatment for CUD is based on a plausible and novel mechanism (i.e., FAAH inhibition) that will restore eCB tone, thereby reducing cannabis use and the withdrawal syndrome. There are very few FAAH-inhibitors that are available or approved for use in humans, and none are available commercially. The proposed study builds on the promising findings of a completed POC study with the same drug at the same dose.

PROJECT SUMMARY Background: There is growing concern about the recreational use of synthetic psychoactive cannabinoids (SPCs) sold as `Spice'. Unlike, delta-9-tetrahydrocannabinol (THC), the principal psychoactive constituent of herbal cannabis, which is a weak efficacy, low affinity, partial agonist of brain cannabinoid receptors (CB1Rs), SPCs are high efficacy, high affinity, full CB1R agonists. Consistent with this profile, while SPCs produce some effects similar to cannabis, they are generally more potent and unpredictable; in fact SPCs have been associated with catastrophic medical and psychiatric adverse outcomes. Despite concerns about the negative consequences of recreational Spice use, there is very little controlled data on the effects of acute or repeated exposure to SPCs on the brain endocannabinoid system or brain function in general. The main purpose of the proposed study, is to compare CB1R availability in Spice dependent (Spice users [SUs]), cannabis dependent (cannabis users [CUs]) and healthy controls (HCs). Furthermore, cognitive test performance will be assessed in order to relate the receptor availability to domains germane to ?real world? functioning. Given the plethora of Spice products and their constituent SPCs, differences in their pharmacology, and the limited scope of an R21 application, we will need to limit the study to the most prevalent SPC around the time around the time the study is expected to be initiated. The latter will identified based on information gleaned from the National Forensic Laboratory Information System (NFLIS), local DEA office, local emergency rooms, news media, Poison Control Centers and blogs about Spice use (e.g., Drugs-Forum). Cognitive test performance will be assessed in order to relate receptor availability to ?real world? functioning. Similarly, cannabinoid-sensitive electrophysiological measures of information processing (P300 and gamma driving) will relate receptor availability to proximal biomarkers of brain function. Primary Hypothesis: Spice users will show lower CB1R availability compared to CUs and HCs. Exploratory Hypotheses: Compared to CUs and HCs, SUs will show worse cognitive test performance, and cannabinoid-sensitive electrophysiological indices of information processing (P300 amplitude and gamma oscillations). Methods: Using the CB1R specific PET ligand [11C]OMAR and High Resolution Research Tomography (HRRT), CB1R availability will be measured in SUs, CUs and HCs. Cognitive function will be assessed using the CANTAB battery. P300 and gamma oscillations will also be measured. Preliminary Results: Spice Users (n=2) show robust reductions in CB1R availability relative to cannabis users (n=11) and healthy controls (n=19). The magnitude of the differences (effects size d) between SUs vs. CUs, and HCs were -1.29 and -6, respectively. Differences between SUs and CUs were comparable in magnitude to the differences between CUs and HCs (~15%, d=1.19).

PROJECT SUMMARY AND ABSTRACT Background: Cannabis is the most commonly used illicit drug by young people. The potency of cannabis has increased and so has the use of highly potent synthetic cannabinoids (`Spice'). Furthermore, the ?medical? and recreational use of cannabis is increasingly being legalized across the U.S. Perceptions of the risks of cannabis use amongst teenagers has declined over the past decade . The initiation of cannabis use typically occurs during adolescence and young adulthood, when the brain is still developing and is most vulnerable to insults, particularly drugs. Therefore, it is important to understand the consequences of chronic cannabinoid exposure on the structure and function of the brain. Repeated administration of cannabinoids to both rodents has been shown to lower synaptic density, but this has yet to be studies in humans. We recently developed [11C]-UCB-J, a tracer for imaging of the synaptic vesicle protein SV2A in vivo. The purpose of this exploratory study is to compare synaptic density in cannabis dependent subjects (CDs) and healthy controls (HCs) and to relate changes in synaptic density to proximal and distal measures of brain activity, namely evoked ? oscillations in the EEG and verbal memory. Furthermore, the relationship between [11C]-UCB-J binding, evoked ? oscillations, verbal memory, and measures of cannabis exposure (age of first use and lifetime exposure) will be explored. Hypotheses: Compared to HCs, CDs will show 1) ? [11C]-UCB-J binding, 2) ? deficits in measures of evoked ? oscillations, and 3) ? deficits in verbal memory. In CD subjects, lower [11C]UCB-J binding will be positively correlated with earlier age of initiation of cannabis use, lifetime cannabis exposure, worse verbal memory and greater deficits in ? oscillations. Methods: We will compare synaptic density in CDs (n=12) vs. HCs (n=12) using [11C]- UCB-J and the High Resolution Research Tomograph. CDs and HCs will also be compared on measures of evoked ? oscillations (auditory steady state response: ASSR) and verbal memory (Rey Auditory Verbal Learning Task: RAVLT). The relationship between [11C]- UCB-J binding, evoked ? oscillations, verbal memory, and measures of cannabis exposure (age of initiation of use and lifetime exposure) will be explored. Pilot data: To demonstrate feasibility, CDs (n=2) and HC (n=6) have been studied; CDs showed reduced SV2A binding of 10% or more (i.e., greater than the margin of test-retest variability) in several brain regions.

PROJECT SUMMARY AND ABSTRACT Background: Converging lines of evidence from postmortem studies provide strong evidence that brain muscarinic M1 receptor deficit is present in a subset of schizophrenia (SZ) patients. M1 receptors are an important target for cognitive deficits in SZ. However, until now, it has not been possible to examine the heterogeneity of SZ with respect to M1 receptor availability in vivo. The development of a novel positron emission tomography (PET) ligand, [11C]EMO, at Yale PET Center provides a unique opportunity to, for the first time, examine in vivo brain muscarinic M1 receptor availability in SZ and, concurrently, elucidate the relationship of M1 receptors to cognitive deficits in SZ. The ligand has high affinity for the M1 receptor, high brain uptake, appropriate kinetics, excellent test-retest reproducibility (? 6% test-retest variability in cortical regions), and presence of a suitable reference region (i.e., cerebellum) demonstrated in blocking studies. This allows for a reliable estimation of specific binding to M1 receptors (BPND) using kinetic modeling. The purpose of this exploratory study is to examine M1 receptor availability in SZ patients and to relate M1 receptor availability to proximal and distal measures of cognitive performance, namely evoked ? oscillations in the EEG and verbal memory. Furthermore, the relationship between hippocampal [11C]EMO availability (BPND), evoked ? oscillations, verbal memory, and measures of illness severity will be explored. Hypotheses: SZ subjects will show lower hippocampal M1 receptor availability as measured using [11C]EMO BPND. Additionally, M1 receptor availability ([11C]EMO BPND) will correlate with verbal memory performance and EEG indices of encoding (? power) during a verbal memory task in SZ. Methods: We will compare M1 receptor availability in SZ and age-, gender-matched healthy controls using [11C]EMO and the High Resolution Research Tomograph (HRRT), a PET scanner with high sensitivity and resolution available for human brain imaging. The relationship between hippocampal [11C]EMO binding, encoding related ? power during a verbal memory task, verbal memory, gender and serum acetylcholine level will be explored. This exploratory study will provide the necessary pilot data to conduct a larger study to fully investigate the heterogeneity of SZ with respect to M1 receptor availability.