The Endocannabinoid System: A New Treatment Target for Obsessive Compulsive Disorder?

Repeated Δ-9-Tetrahydrocannabinol administration dose dependently increases stablished schedule-induced drinking

RATIONALE

Schedule-induced drinking (SID) reproduces an excessive and repetitive behavioural pattern that has led to propose this procedure as an animal model to study compulsive behaviours. Although it is known that cannabis can cause several adverse effects, in recent years there has been great interest in the medical application of cannabis derivatives for obsessive-compulsive related disorders.

OBJECTIVES

The present study investigated the effects of repeated THC administration on rates of previously acquired SID, as well as the possible alteration of its temporal distribution along inter-food intervals.

METHODS

Male Wistar rats acquired SID under a 30 min fixed-time 30-sec food delivery schedule (from 30 to 43 sessions to reach a stable level). Thereafter, 5 or 10 mg/kg daily i.p. injections of THC or vehicle were repeatedly administered for 7 days to evaluate the effects on SID.

RESULTS

Repeated THC administration at a dose of 5 mg/kg resulted in an increase on licking. Surprisingly, no effects on SID were observed with the 10 mg/kg dose. However, magazine entries were reduced with both THC doses. THC also modified the temporal distributions of licking and magazine entries during inter-food intervals.

CONCLUSIONS

The present results show that repeated THC administration may (i) increase induced licking at moderate doses, (ii) reduce magazine entries, and (iii) affect the temporal pattern of SID. These findings suggest that THC does not appear to be beneficial to reduce compulsive behaviour in this animal model, while another collateral effect of THC -such as a greater habitual-like behaviour- needs to be considered.

Selective alterations of endocannabinoid system genes expression in obsessive compulsive disorder

Obsessive Compulsive Disorder (OCD) is listed as one of the top 10 most disabling neuropsychiatric conditions in the world. The neurobiology of OCD has not been completely understood and efforts are needed in order to develop new treatments. Beside the classical neurotransmitter systems and signalling pathways implicated in OCD, the possible involvement of the endocannabinoid system (ECS) has emerged in pathophysiology of OCD. We report here selective downregulation of the genes coding for enzymes allowing the synthesis of the endocannabinoids. We found reduced DAGLα and NAPE-PLD in blood samples of individuals with OCD (when compared to healthy controls) as well as in the amygdala complex and prefrontal cortex of dopamine transporter (DAT) heterozygous rats, manifesting compulsive behaviours. Also mRNA levels of the genes coding for cannabinoid receptors type 1 and type 2 resulted downregulated, respectively in the rat amygdala and in human blood. Moreover, NAPE-PLD changes in gene expression resulted to be associated with an increase in DNA methylation at gene promoter, and the modulation of this gene in OCD appears to be correlated to the progression of the disease. Finally, the alterations observed in ECS genes expression appears to be correlated with the modulation in oxytocin receptor gene expression, consistently with what recently reported. Overall, we confirm here a role for ECS in OCD at both preclinical and clinical level. Many potential biomarkers are suggested among its components, in particular NAPE-PLD, that might be of help for a prompt and clear diagnosis.

Genetic influences on the interplay between obsessive-compulsive behavior symptoms and cannabis use during adolescence

INTRODUCTION

There are overlapping biological origins and behaviors associated with obsessive-compulsive symptoms (OCS) and cannabis use. There is also evidence that OCS and cannabis use are associated over time. Thus, we investigated polygenic predisposition for OCS as predictive of OCS and cannabis use from age 17 to 19. We hypothesized that greater genetic risk for OCS would predict both OCS and cannabis use.

METHODS

The current study used participants from the Project Alliance 1 study, a US-based sample, for whom genomic, OCS, and cannabis use data were available (n = 547). Polygenic risk scores (PRS) were formed via a meta-genome-wide association study on OCS and examined as a predictor of OCS and cannabis use at age 17 and 19. The sample was diverse (52.4% male; 45% European American, 30% African American, 14% multiracial, 5% Hispanic/Latino, 4% Asian American, and 2% other groups). Sensitivity analysis was performed by gender for European American and African American subsamples.

RESULTS

Across the whole sample, the greater polygenic risk for OCS was negatively associated with cannabis use at age 17 and positively associated with OCS at 19. Cannabis use at age 17 was positively associated with OCS at age 19. The association between polygenic risk for OCS and cannabis use at age 17 was replicated in European American males, whereas the association between cannabis use at age 17 and OCS at age 19 was replicated in African American males.

CONCLUSIONS

Cannabis use may exacerbate OCS through adolescence, and genetic predisposition for OCS may be associated with lower cannabis use in efforts to avoid exacerbation of OCS.

Cannabis use and related clinical variables in patients with obsessive-compulsive disorder

OBJECTIVE

Limited studies have investigated cannabis use in patients with obsessive-compulsive disorder (OCD), despite its widespread use by patients with psychiatric illnesses. The aim of this study was to assess the frequency, correlates, and clinical impact of cannabis use in an Italian sample of patients with OCD.

METHODS

Seventy consecutive outpatients with OCD were recruited from a tertiary specialized clinic. To assess cannabis-related variables, patients completed a questionnaire developed for the purpose of this study, investigating cannabis use-related habits and the influence of cannabis use on OCD symptoms and treatments. A set of clinician and self-reported questionnaires was administered to measure disease severity. The sample was then divided into three subgroups according to the pattern of cannabis use: "current users" (CUs), "past-users" (PUs), and "non-users" (NUs).

RESULTS

Approximately 42.8% of patients reported lifetime cannabis use and 14.3% reported current use. Approximately 10% of cannabis users reported an improvement in OCD symptoms secondary to cannabis use, while 23.3% reported an exacerbation of anxiety symptoms. CUs showed specific unfavorable clinical variables compared to PUs and NUs: a significant higher rate of lifetime use of tobacco, alcohol, and other substances, and a higher rate of pre-OCD onset comorbidities. Conversely, the three subgroups showed a similar severity of illness.

CONCLUSION

A considerable subgroup of patients with OCD showed a predisposition towards cannabis use and was associated with some specific clinical characteristics, suggesting the need for targeted consideration and interventions in this population.

Chronic ∆-9-tetrahydrocannabinol administration delays acquisition of schedule-induced drinking in rats and retains long-lasting effects

RATIONALE

Schedule-induced drinking (SID) is a behavioural phenomenon characterized by an excessive and repetitive drinking pattern with a distinctive temporal distribution that has been proposed as a robust and replicable animal model of compulsivity. Despite cannabis currently being the most widely consumed illicit drug, with growing interest in its clinical applications, little is known about the effects of ∆-9-tetrahydrocannabinol (THC) on SID.

OBJECTIVES

The effects of chronic and acute THC administration on SID acquisition, maintenance and extinction were studied, as were the effects of such administrations on the distinctive temporal distribution pattern of SID.

METHODS

THC (5 mg/kg i.p.), or the corresponding vehicle, was administered to adult Wistar rats for 14 days in a row. Subsequently, THC effects on SID acquisition were tested during 21 sessions using a 1-h fixed-time 60-s food delivery schedule. Acute effects of THC were also evaluated after SID development. Finally, two extinction sessions were conducted to assess behavioural persistence.

RESULTS

The results showed that previous chronic THC treatment delayed SID acquisition and altered the distinctive behavioural temporal distribution pattern during sessions. Moreover, acute THC administration after SID development decreased SID performance in animals chronically pre-treated with the drug. No great persistence effects were observed during extinction in animals pre-treated with THC.

CONCLUSIONS

These results suggest that chronic THC affects SID development, confirming that it can disrupt learning, possibly causing alterations in time estimation, and also leads to animals being sensitized when they are re-exposed to the drug after long periods without drug exposure.

Possible actions of cannabidiol in obsessive-compulsive disorder by targeting the WNT/β-catenin pathway

Obsessive-compulsive disorder (OCD) is a neuropsychiatric disorder characterized by recurrent and distinctive obsessions and/or compulsions. The etiologies remain unclear. Recent findings have shown that oxidative stress, inflammation, and glutamatergic pathways play key roles in the causes of OCD. However, first-line therapies include cognitive-behavioral therapy but only 40% of the patients respond to this first-line therapy. Research for new treatment is mandatory. This review focuses on the potential effects of cannabidiol (CBD), as a potential therapeutic strategy, on OCD and some of the presumed mechanisms by which CBD provides its benefit properties. CBD medication downregulates GSK-3β, the main inhibitor of the WNT/β-catenin pathway. The activation of the WNT/β-catenin could be associated with the control of oxidative stress, inflammation, and glutamatergic pathway and circadian rhythms dysregulation in OCD. Future prospective clinical trials could focus on CBD and its different and multiple interactions in OCD.

Trichotillomania and excoriation disorder: Primary care implications

ABSTRACT

Trichotillomania and excoriation disorder are two psychiatric conditions that have similar origins to obsessive compulsive disorder. Both can cause patients significant distress and lead to medical consequences. It is important that primary care NPs identify and refer these individuals for psychiatric treatment.

Patterns of Cannabis Use Among Individuals with Obsessive-Compulsive Disorder: Results from an Internet Survey

BACKGROUND

Americans increasingly use cannabis, including those with psychiatric disorders. Yet little is known about cannabis use among individuals with obsessive-compulsive disorder (OCD). Thus, we conducted the first survey of cannabis users with OCD.

METHODS

Adults with OCD (i.e., prior professional diagnosis and/or score above the cutoff on a validated scale) who reported using cannabis were recruited from internet sources to complete a survey querying demographic information, medical/psychiatric history, cannabis use patterns, and perceived cannabis effects.

RESULTS

Of 1096 survey completers, 601 met inclusion criteria. Inhalation/cannabis flower were the most common method/formulation participants endorsed; most identified using high-potency cannabis products; 42% met criteria for cannabis use disorder. Nearly 90% self-reported using cannabis medicinally, 33.8% had a physician's recommendation, and 29% used specifically to manage OCD symptoms. Most participants reported cannabis improved obsessions/compulsions; those with increased obsession severity perceived less benefit. Finally, most participants were not receiving evidence-based OCD treatment, and the odds of receiving treatment decreased with increased cannabis use.

CONCLUSIONS

In this survey, participants with OCD reported both subjective benefits and harms from cannabis use. Future research should clarify the risks and benefits of cannabis use to those with OCD and develop treatment models to better support this population.

Human Laboratory Models of Cannabis Use: Applications for Clinical and Translational Psychiatry Research

Cannabis is increasingly used by individuals with mental health diagnoses and often purported to treat anxiety and various other psychiatric symptoms. Yet support for using cannabis as a psychiatric treatment is currently limited by a lack of evidence from rigorous placebo-controlled studies. While regulatory hurdles and other barriers make clinical trials of cannabis challenging to conduct, addiction researchers have decades of experience studying cannabis use in human laboratory models. These include methods to control cannabis administration, to delineate clinical and mechanistic aspects of cannabis use, and to evaluate potential treatment applications for cannabis and its constituents. In this paper, we review these human laboratory procedures and describe how each can be applied to study cannabis use in patients with psychiatric disorders. Because anxiety disorders are among the most common psychiatric illnesses affecting American adults, and anxiety relief is also the most commonly-reported reason for medicinal cannabis use, we focus particularly on applying human laboratory models to study cannabis effects in individuals with anxiety and related disorders. Finally, we discuss how these methods can be integrated to study cannabis effects in other psychiatric conditions and guide future research in this area.

Acute Effects of Cannabis on Symptoms of Obsessive-Compulsive Disorder

BACKGROUND

Little is known about the the acute effects of cannabis on symptoms of OCD in humans. Therefore, this study sought to: 1) examine whether symptoms of OCD are significantly reduced after inhaling cannabis, 2) examine predictors (gender, dose, cannabis constituents, time) of these symptom changes and 3) explore potential long-term consequences of repeatedly using cannabis to self-medicate for OCD symptoms, including changes in dose and baseline symptom severity over time.

METHOD

Data were analyzed from the app Strainprint® which provides medical cannabis patients a means of tracking changes in symptoms as a function of different doses and strains of cannabis across time. Specifically, data were analyzed from 87 individuals self-identifying with OCD who tracked the severity of their intrusions, compulsions, and/or anxiety immediately before and after 1,810 cannabis use sessions spanning a period of 31 months.

RESULTS

Patients reported a 60% reduction in compulsions, a 49% reduction in intrusions, and a 52% reduction in anxiety from before to after inhaling cannabis. Higher concentrations of CBD and higher doses predicted larger reductions in compulsions. The number of cannabis use sessions across time predicted changes in intrusions, such that later cannabis use sessions were associated with smaller reductions in intrusions. Baseline symptom severity and dose remained fairly constant over time.

LIMITATIONS

The sample was self-selected, self-identified as having OCD, and there was no placebo control group.

CONCLUSIONS

Inhaled cannabis appears to have short-term beneficial effects on symptoms of OCD. However, tolerance to the effects on intrusions may develop over time.

Investigational and Experimental Drugs to Treat Obsessive-Compulsive Disorder

Treatment-resistance is a frequent condition for obsessive-compulsive disorder (OCD). Over the past decades, a lot of effort has been made to address this issue, and several augmentation strategies of serotonergic drugs have been investigated. Antidopaminergic drugs are considered the first choice as augmentation strategy for treatment-resistant OCD patients, but they seem to work only for a subset of patients, and none of them have been officially approved for OCD. Recently, the role of glutamate and inflammation in OCD pathophysiology clearly emerged, and this has led to several investigations on glutamatergic and anti-inflammatory agents. Results seem promising but still inconclusive. Probiotic interventions (considered to modulate the immune systems and the brain activity) are gaining attention in several psychiatric fields but are still at their early stages in the OCD field. Research on new treatment approaches for OCD is moving forward, and more than one hundred interventional trials are ongoing around the world. While the vast majority of these trials involve neuromodulation and psychotherapeutic approaches, only a small proportion (around 20%) involve the investigation of new pharmacological approaches (tolcapone, nabilone, psilocybin, troriluzole, nitrous oxide, rituximab, naproxen, and immunoglobulins). Here, we provide a comprehensive review of investigational and experimental drugs to treat OCD.

Cannabis Use in People With Obsessive-Compulsive Symptomatology: Results From a Mexican Epidemiological Sample

Recent studies suggest that the endocannabinoid system could play an important role in the physiopathology of obsessive-compulsive disorder (OCD). There are reports of effective treatment with derivatives of tetrahydrocannabinol (THC). The study of the genetic factor associated with psychiatric disorders has made possible an exploration of its contribution to the pharmacological response. However, very little is known about the genetic factor or the prevalence of cannabis use in the Mexican population with OCD. The objective of this study is to compare the prevalence of use and dependence on cannabis in individuals with obsessive-compulsive symptomatology (OCS) with that of individuals with other psychiatric symptoms (psychosis, depression, and anxiety), and to explore the association between genetic risk and use. The study includes a total of 13,130 individuals evaluated in the second stage of the 2016 National Survey of Drug, Alcohol, and Tobacco Use (Encodat 2016), with genetic analysis (polygenic risk scoring) of a subsample of 3,521 individuals. Obsessive symptomatology had a prevalence of 7.2% and compulsive symptomatology a prevalence of 8.6%. The proportion of individuals with OCS who had ever used cannabis was 23.4%, and of those with cannabis dependency was 2.7%, the latter figure higher than that in individuals with other psychiatric symptoms (hypomania, 2.6%; anxiety, 2.8%; depression, 2.3%), except psychosis (5.9%). Individuals with OCS who reported using cannabis had an increased genetic risk for cannabis dependence but not for OCD. We thus cannot know how the increased genetic risk of cannabis dependence in people with OCD is influenced by their pharmacological response to derivatives of THC. The results, however, suggest paths for future studies.

Challenges in the Diagnosis and Assessment in Patients with Tourette Syndrome and Comorbid Obsessive-Compulsive Disorder

Tourette syndrome (TS) is characterized by the presence of vocal and motor tics with an onset in childhood. In almost 80% of patients psychiatric comorbidities coexist, particularly, attention deficit/hyperactivity disorder (ADHD), obsessive-compulsive disorder (OCD) or behavior (OCB), depression, anxiety, rage attacks, and self-injurious behaviour (SIB). In this review, we discuss current state of the art regarding diagnosis and assessment of tics and OCD in patients with TS as well as challenges related to differential diagnosis between tics and OCD-related phenomena based on a systematic literature search. While in most cases clinical symptoms can be easily classified as either tics or OCB/OCD, some phenomena lay on the frontier between tics and compulsions/obsessions. For example, compulsions may resemble tics and, vice versa, sequences of motor tics may be misdiagnosed as compulsions. Accordingly, the terms "compulsive tics" and "cognitive tics" have been introduced. The most common and typical OCD symptom in patients with TS are "just right" phenomena, which also may show an overlap with tics, since patients may perform tics repeatedly until this feeling is achieved. Similarly, repetitive behaviors in patients with TS may manifest in a more "tic-like" or a more "OCD-like" type. Furthermore, SIB shows similarities with both tics and OCD. Until today, it is unclear how to classify this symptom best, although from most recent research a closer relationship between SIB and tics is suggested. In this review, in addition, we illustrate differences of the clinical spectrum of OCD in patients with TS compared to those with "pure OCD" without tics. To assess tics, the revised version of the Yale Global Tic Severity Scale (YGTSS-R) should be used, while for the assessment of OCD, the Yale Brown Obsessive Compulsive Disorder Scale (Y-BOCS) is recommended. Finally, we briefly summarize treatment strategies for tics and OCB/OCD in patients with TS.

Innovations in the Delivery of Exposure and Response Prevention for Obsessive-Compulsive Disorder

Obsessive-Compulsive Disorder is an important cause of global health-related disability. In the last several decades, exposure and response prevention (EX/RP) has emerged as one of the most evidence-based treatments for adult and pediatric OCD. Recommended as a first-line treatment in practice guidelines for OCD, EX/RP, when expertly delivered, can be superior to serotonin reuptake inhibitor (SRI) medications alone and superior to adding antipsychotic medication to augment SRI treatment response. Despite a robust evidence base, EX/RP is not widely available. Moreover, although effective, only about half of patients who receive a standard course of EX/RP will achieve remission.This chapter will review innovations in delivering EX/RP, focusing on technology-based methods designed to increase access to EX/RP and translational neuroscience approaches to personalizing and optimizing EX/RP. Technology-based innovations to deliver EX/RP include video conferencing, internet-based treatment, and smartphone apps. Of these, internet-based, clinician-supported treatment has the most evidence base to date. Relevant to all technology-based innovations are the need for advances in the ethical, regulatory and financial aspects of understanding how access to EX/RP may be delivered to individuals of diverse socioeconomic backgrounds in accordance with professional standards and regulations and covered by healthcare.Advances in our understanding of the neural processes underlying learning and memory have led to new ways to combine EX/RP with medications, behavioral interventions, or neuromodulatory methods, with the goal of enhancing the functioning of brain circuits that subserve fear processing and cognitive control. Among the pharmacological approaches to enhancing EX/RP outcome, both ketamine and cannabinoids show promise in small open trials but are in need of further study. Studies to train cognitive control are at an early stage of development yet provide preliminary evidence that training neural processes may be a new path to personalize treatment. How best to combine EX/RP with different types of neuromodulation is being actively studied.Together these innovations in the delivery of EX/RP for OCD hold great promise for improving outcomes of care for individuals with OCD by increasing the availability and the individual treatment effects of this already effective treatment.

Role of Cannabinoid Receptors in Psychological Disorder

Cannabinoid receptors, located throughout the body, are part of the endocannabinoid system. Cannabinoid CB1 and CB2 receptors are G protein-coupled receptors present from the early stages of gestation, which is involved in various physiological processes, including appetite, pain-sensation, mood, and memory. Due to the lipophilic nature of cannabinoids, it was initially thought that these compounds exert several biological effects by disrupting the cell membrane nonspecifically. Recent biochemical and behavioral findings have demonstrated that blockade of CB1 receptors engenders antidepressant-like neurochemical changes (increases in extracellular levels of monoamines in cortical but not subcortical brain regions) and behavioral effects consistent with antidepressant/antistress activity. We aim to define various roles of cannabinoid receptors in modulating signaling pathways and association with several pathophysiological conditions.

Psychiatric emergency care during Coronavirus 2019 (COVID 19) pandemic lockdown: results from a Department of Mental Health and Addiction of northern Italy

BACKGROUND

The current COVID-19 pandemic and the consequent containment measures are leading to increasing mental health issues both in psychiatric patients and general population.

OBJECTIVE

We aimed to compare the number and characteristics of emergency psychiatric consultations during the phase 1 of lockdown with respect to the same period in 2019 in a Department of Mental Health and Addiction (DMHA) located in Lombardy region.

METHODS

We conducted a cross-sectional study including subjects consecutively admitted to two psychiatric emergency rooms of DMHA in Monza, Lombardy, Italy. Sociodemographic data, clinical characteristics, referred symptoms, diagnosis and information on patients' illness course following the emergency consultations were collected. No subjects were excluded for the purposes of the study.

RESULTS

Between February 21st and May 3rd 2020, there was a marked reduction in the number of psychiatric emergency consultations, if compared to the same period of 2019. Subjects who were living in psychiatric residential treatment facilities, had cannabis addiction and a diagnosis of obsessive-compulsive disorder were significantly more likely to present to emergency psychiatric consultations during lockdown.

CONCLUSIONS

COVID-19 epidemic may have a negative impact on more vulnerable individuals. Strategies to enhance relapse prevention and the use of alternative approaches as e-health technologies should be promoted.

Acute effects of cannabinoids on symptoms of obsessive-compulsive disorder: A human laboratory study

BACKGROUND

Preclinical data implicate the endocannabinoid system in the pathology underlying obsessive-compulsive disorder (OCD), while survey data have linked OCD symptoms to increased cannabis use. Cannabis products are increasingly marketed as treatments for anxiety and other OCD-related symptoms. Yet, few studies have tested the acute effects of cannabis on psychiatric symptoms in humans.

METHODS

We recruited 14 adults with OCD and prior experience using cannabis to enter a randomized, placebo-controlled, human laboratory study to compare the effects on OCD symptoms of cannabis containing varying concentrations of Δ-9-tetrahydrocannabinol (THC) and cannabidiol (CBD) on OCD symptoms to placebo. We used a within-subjects design to increase statistical power. Across three laboratory sessions, participants smoked three cannabis varietals in random order: placebo (0% THC/0% CBD); THC (7.0% THC/0.18% CBD); and CBD (0.4% THC/10.4% CBD). We analyzed acute changes in OCD symptoms, state anxiety, cardiovascular measures, and drug-related effects (e.g., euphoria) as a function of varietal.

RESULTS

Twelve participants completed the study. THC increased heart rate, blood pressure, and intoxication compared with CBD and placebo. Self-reported OCD symptoms and anxiety decreased over time in all three conditions. Although OCD symptoms did not vary as a function of cannabis varietal, state anxiety was significantly lower immediately after placebo administration relative to both THC and CBD.

CONCLUSIONS

This is the first placebo-controlled investigation of cannabis in adults with OCD. The data suggest that smoked cannabis, whether containing primarily THC or CBD, has little acute impact on OCD symptoms and yields smaller reductions in anxiety compared to placebo.

Cannabis Improves Obsessive-Compulsive Disorder-Case Report and Review of the Literature

Although several lines of evidence support the hypothesis of a dysregulation of serotoninergic neurotransmission in the pathophysiology of obsessive-compulsive disorder (OCD), there is also evidence for an involvement of other pathways such as the GABAergic, glutamatergic, and dopaminergic systems. Only recently, data obtained from a small number of animal studies alternatively suggested an involvement of the endocannabinoid system in the pathophysiology of OCD reporting beneficial effects in OCD-like behavior after use of substances that stimulate the endocannabinoid system. In humans, until today, only two case reports are available reporting successful treatment with dronabinol (tetrahydrocannabinol, THC), an agonist at central cannabinoid CB1 receptors, in patients with otherwise treatment refractory OCD. In addition, data obtained from a small open uncontrolled trial using the THC analogue nabilone suggest that the combination of nabilone plus exposure-based psychotherapy is more effective than each treatment alone. These reports are in line with data from a limited number of case studies and small controlled trials in patients with Tourette syndrome (TS), a chronic motor and vocal tic disorder often associated with comorbid obsessive compulsive behavior (OCB), reporting not only an improvement of tics, but also of comorbid OCB after use of different kinds of cannabis-based medicines including THC, cannabis extracts, and flowers. Here we present the case of a 22-year-old male patient, who suffered from severe OCD since childhood and significantly improved after treatment with medicinal cannabis with markedly reduced OCD and depression resulting in a considerable improvement of quality of life. In addition, we give a review of current literature on the effects of cannabinoids in animal models and patients with OCD and suggest a cannabinoid hypothesis of OCD.