Dose-response effect between cannabis use and psychosis liability in a non-clinical population: evidence from a snowball sample

Cannabis use among patients presenting to the emergency department for psychosis: Associations with restraint use, medication administration, psychiatric hospitalization, and repeat visits

Cannabis use is associated with increased severity of psychotic symptoms and the risk of acute agitation and aggressive behavior in inpatient (IP) and outpatient settings. Whether or not cannabis use is associated with increased acuity of psychosis-related ED presentations and risk of repeat ED visits for psychosis is unclear. In this retrospective study of 2,134 ED visits for acute psychosis, we investigated the risk of physical restraint, parenteral medication administration, psychiatric hospitalization, and recurrent ED visits. We examined ED visits between March 1, 2019 and February 28, 2021 based on urinary Tetrahydrocannabinol (THC) screen status (positive vs negative vs no screen). The risk of physical restraint, parenteral antipsychotic, and benzodiazepine administration was significantly greater in ED visits with a positive THC screen compared to those with a negative or no THC screen. We did not find an association between a positive urinary THC screen and IP hospitalization or the risk of recurrent ED presentation for psychosis within 90 days. These findings suggest that positive urinary THC may predict acute agitation or acuity of symptoms in ED settings and underscores the importance of screening for THC during ED presentations for psychosis.

A network approach to relationships between cannabis use characteristics and psychopathology in the general population

Cannabis use characteristics, such as earlier initiation and frequent use, have been associated with an increased risk for developing psychotic experiences and psychotic disorders. However, little is known how these characteristics relate to specific aspects of sub-clinical psychopathology in the general population. Here, we explore the relationships between cannabis use characteristics and psychopathology in a large general population sample (N = 2,544, mean age 29.2 years, 47% women) by employing a network approach. This allows for the identification of unique associations between two cannabis use characteristics (lifetime cumulative frequency of cannabis use, age of cannabis use initiation), and specific psychotic experiences and affective symptoms, while controlling for early risk factors (childhood trauma, urban upbringing). We found particularly pronounced unique positive associations between frequency of cannabis use and specific delusional experiences (persecutory delusions and thought broadcasting). Age of cannabis use initiation was negatively related to visual hallucinatory experiences and irritability, implying that these experiences become more likely the earlier use is initiated. Earlier initiation, but not lifetime frequency of cannabis use, was related to early risk factors. These findings suggest that cannabis use characteristics may contribute differentially to risk for specific psychotic experiences and affective symptoms in the general population.

The association between sleep quality and attenuated psychotic symptoms

AIM

To determine if poor sleep makes a unique contribution in predicting the likelihood of experiencing six or more attenuated psychotic symptoms and associated distress, after examining and controlling for sociodemographic factors, depression and drug/alcohol use.

METHOD

An online survey was conducted using Amazon's online crowdsourcing service Mechanical Turk (MTurk). The sample was 1013 adults (18 to 36 years) from the general population in the United States. The survey consisted of the Prodromal Questionnaire 16 (PQ-16), the Pittsburgh Sleep Quality Index, the Patient Health Questionnaire 9, the Drug Abuse Screening Test 10 and the Alcohol Use Disorders Identification Test. Regression analyses were performed with the PQ-16 as the dependent variable, and sleep quality as the predictor variable, holding constant sociodemographic variables, depression, and alcohol/drug abuse.

RESULTS

37% of the sample endorsed six or more PQ-16 items, which may be suggestive of an at-risk mental state, with sleep disturbance significantly increasing the likelihood (Odds ratio 2.09 < .001) of endorsing six or more PQ-16 items. After controlling for sociodemographic variables, depression and drug/alcohol abuse, poor sleep quality made a unique contribution of 5.8% of the variance accounted for in level of distress experienced by attenuated psychotic symptoms.

CONCLUSION

Effective treatment of sleep disturbance may reduce the likelihood ofexperiencing attenuated psychotic symptoms and associated distress.

The Behavioral Sequelae of Cannabis Use in Healthy People: A Systematic Review

Background: Cannabis is known to have a broad range of effects on behavior, including experiencing a "high" and tranquility/relaxation. However, there are several adverse behavioral sequalae that can arise from cannabis use, depending on frequency of use, potency (e.g., THC content), age of onset, and cumulative exposure. This systematic review examined evidence for cannabis-related adverse behavioral sequalae in otherwise healthy human subjects. Methods: Following PRISMA guidelines, we conducted a systematic review of cross-sectional and longitudinal studies from 1990 to 2020 that identified cannabis-related adverse behavioral outcomes in subjects without psychiatric and medical co-morbidities from PubMed and PsychInfo searches. Key search terms included "cannabis" OR "tetrahydrocannabinol" OR "cannabidiol" OR "marijuana" AND "anxiety" OR "depression" OR "psychosis" OR "schizophrenia" "OR "IQ" OR "memory" OR "attention" OR "impulsivity" OR "cognition" OR "education" OR "occupation". Results: Our search detected a total of 2,870 studies, from which we extracted 124 relevant studies from the literature on cannabis effects in the non-clinical population. Effects of cannabis on several behavioral sequelae including cognition, motivation, impulsivity, mood, anxiety, psychosis intelligence, and psychosocial functioning were identified. The preponderance of the evidence suggests that frequency of cannabis use, THC (but not CBD) content, age of onset, and cumulative cannabis exposure can all contribute to these adverse outcomes in individuals without a pre-existing medical condition or psychiatric disorder. The strongest evidence for the negative effects of cannabis are for psychosis and psychosocial functioning. Conclusions: Although more research is needed to determine risk factors for development of adverse behavioral sequelae of cannabis use, these findings underline the importance of understanding vulnerability to the adverse effects of cannabis, which has implications for prevention and treatment of problematic cannabis use.

Link between personality and response to THC exposure

The effects of cannabis reported by users range from experiences of euphoria and anxiolytic effects to paranoia, anxiety, and increased risk of depression. Attempts to reconcile the apparent contradictions in user response have not been conclusive. Here, we utilized selectively-bred stress-resilient socially dominant (Dom) and stress-sensitive socially submissive (Sub) mice to elucidate this contradiction. Following short-term, repeated treatment with delta-9-tetrahydrocannabinol (THC) at two different doses (1.5 mg/kg and 15 mg/kg), Sub mice presented significant place-aversion in a Conditioned Place Preference paradigm at a high dose, whereas Dom mice displayed no place preference or aversion. Forced Swim test conducted after 6-week of washout period, revealed differential impact of the two THC doses depending upon behavioral pattern. Specifically, the low dose alleviated depressive-like behavior in Sub mice, while the high dose produced the opposite effect in Dom mice. Interestingly, corticosterone concentration in serum was elevated at the high dose regardless of the mice-population tested. We conclude here that differences in dominance behavior and stress vulnerability are involved in the regulation of cannabis response among users and should be considered when prescribing THC-containing medications to patients.

Cannabis use as a risk factor for psychotic-like experiences: A systematic review of non-clinical populations evaluated with the Community Assessment of Psychic Experiences

AIM

Epidemiological data have provided evidence that psychotic-like experiences (PLEs) can occur in the general population, not necessarily accompanied by the impairment and suffering observed in formal psychiatric diagnoses. According to the psychosis continuum hypothesis, PLEs would be subject to the same risk factors as frank psychosis. The aim of this review was to summarize observational studies that evaluated cannabis use as a risk factor for PLEs as determined by the Community Assessment of Psychic Experiences in non-clinical samples. The instrument composed of 3 dimensions-positive, negative and depressive-is a scale specifically designed to assess the occurrence, frequency and impact of PLEs in non-clinical population.

METHODS

We searched PubMed/Medline, Web of Science and PsycInfo electronic databases for indexed peer-reviewed studies published until September 2017.

RESULTS

We initially identified 100 articles. The PRISMA model for systematic reviews was used and 19 full-text articles were analysed. In general, the findings suggested that the higher the cannabis use and the younger the participants, the higher the reports of PLEs, although associations were more consistent for the positive dimension.

CONCLUSIONS

More attention should be paid to the understanding of the risk factors of PLEs in the general population, since these experiences are themselves a risk for psychotic disorders.

A Cross-Sectional Study on the Prevalence and Risk Correlates of Mental Disorders: The GRANADΣP Study

This is a cross-sectional study of participants from a population census living in the province of Granada (Spain). A total of 1176 persons were contacted, 367 (31%) refused and 54 (6.7%) needed substitution. A final sample of 809 participants (response rate, 69.3%) were screened for mental disorder (MD) using the MINI International Neuropsychiatric Interview, a comprehensive interview validated to generate diagnoses compatible with ICD-10/DSM-4 criteria. Current (1-month) prevalence for any MD was 11.3% (95% confidence interval [CI], 9.7%-13.4%; affective 8.2%, anxiety 9.6%, psychotic 2.1%, addiction 1.8%, personality disorder 3.6%). Lifetime MD prevalence was 24.6% (95% CI, 21.6-27.6; affective 14.9%, anxiety 15.5%, psychotic 3.4%, addiction 4.4%, personality disorder 3.6%). Female sex was associated with MD, but this appeared partially due to higher levels of neuroticism among women. MD also correlated significantly with cannabis use, family history of MD, higher social adversity, higher suicide risk, poorer physical health, poorer cognitive performance, and personality problems.

The associations between psychotic experiences and substance use and substance use disorders: findings from the World Health Organization World Mental Health surveys

BACKGROUND AND AIMS

Prior research has found bidirectional associations between psychotic experiences (PEs) and selected substance use disorders. We aimed to extend this research by examining the bidirectional association between PEs and various types of substance use (SU) and substance use disorders (SUDs), and the influence of antecedent mental disorders on these associations.

DESIGN, SETTING, PARTICIPANTS AND MEASUREMENTS

We used data from the World Health Organization World Mental Health surveys. A total of 30 902 adult respondents across 18 countries were assessed for (a) six types of life-time PEs, (b) a range of types of SU and DSM-IV SUDs and (c) mental disorders using the Composite International Diagnostic Interview. Discrete-time survival analyses based on retrospective age-at-onset reports examined the bidirectional associations between PEs and SU/SUDs controlling for antecedent mental disorders.

FINDINGS

After adjusting for demographics, comorbid SU/SUDs and antecedent mental disorders, those with prior alcohol use disorders [odds ratio (OR) = 1.6, 95% confidence interval (CI) = 1.2-2.0], extra-medical prescription drug use (OR = 1.5, 95% CI = 1.1-1.9), alcohol use (OR = 1.4, 95% CI = 1.1-1.7) and tobacco use (OR = 1.3, 95% CI = 1.0-1.8) had increased odds of subsequent first onset of PEs. In contrast, those with temporally prior PEs had increased odds of subsequent onset of tobacco use (OR = 1.5, 95% CI = 1.2-1.9), alcohol use (OR = 1.3, 95% CI = 1.1-1.6) or cannabis use (OR = 1.3, 95% CI = 1.0-1.5) as well as of all substance use disorders (ORs ranged between 1.4 and 1.5). There was a dose response relationship between both count and frequency of PEs and increased subsequent odds of selected SU/SUDs.

CONCLUSIONS

Associations between psychotic experiences (PEs) and substance use/substance use disorders (SU/SUDs) are often bidirectional, but not all types of SU/SUDs are associated with PEs. These findings suggest that it is important to be aware of the presence of PEs within those with SUDs or at risk of SUDs, given the plausibility that they may each impact upon the other.

Sex and age differences in risk factors of marijuana involvement during adolescence

Objectives

We aimed to examine whether there are sex and age differences in psychosocial risk factors of marijuana use during adolescence.

Methods

Data were drawn from 57,767 adolescents (8^th and 10^th graders) from the 2012-2013 Monitoring the Future study. We examined the association between socio-demographic and behavioral correlates with different frequencies of past-year marijuana use (non-use, occasional use: <10 time, frequent use: 10-39 times, and regular use: 40+ times). We further investigated whether these associations were similar for boys and girls of different ages.

Results

Overall, 20.6% of the adolescents reported past-year marijuana use: 12.1% occasional use, 4.3% frequent use, and 3.8% regular use. Girls were less likely to be frequent and regular marijuana users (frequent use: OR=0.83 [0.75, 0.93]; regular use: OR=0.41 [0.36, 0.48]) while no sex difference was noted for occasional use. Also, the odds of deviant behaviors were higher as the frequencies of marijuana use were higher. Compared to younger girls, older boys and girls had higher association between all levels of marijuana use and low self-esteem, low perceived harm, peer influence and perceived easy access. Besides, younger boys were more likely than younger girls to report an association between regular marijuana use with low self-esteem, peer influence, and perceived easy access but not with perceived low harm.

Conclusions/Importance

Findings suggest the relationship between these psychosocial correlates and frequency of marijuana involvement varies across sex and age groups. These variations ask for a nuanced approach to prevention of marijuana involvement in different groups of youth.

Influence of depressive symptoms on distress related to positive psychotic-like experiences in women

The Community Assessment of Psychic Experiences (CAPE) is an effective instrument for detection of the presence of psychotic symptoms and associated distress in the general population. However, little research has studied distress associated with positive psychotic-like experiences (PLEs). Our aim is to study PLE-related distress using the CAPE. In this study we analysed factors associated with differences in PLE-related distress in a sample of 200 non-clinical participants recruited by snowball sampling. Presence of PLEs and related psychological distress was measured using the CAPE questionnaire. The influence of age, gender, educational level and drug use was studied. In univariate analysis we found that gender and CAPE positive, depressive and negative scores, were associated with CAPE positive distress. Using multiple linear regression, we found that only the effect of gender, and the interaction between frequency of depression and gender, remained statistically significant. In our sample interaction between gender and depressive symptoms is a determining factor in distress associated with positive PLEs. The results of this study may be useful for the implementation of prevention programs.

Personal and Professional Attitudes and Behavioral Patterns Concerning Cannabis Use of Teachers and Youth Workers in Israel

Professionals working with adolescents may have significant influence on the pro– or anti–cannabis use norms of those adolescents. This study is the first to explore the personal and professional attitudes and behavioral patterns of teachers and youth workers (TYW) regarding the use of cannabis. Self-report anonymous questionnaires were distributed to 135 teachers and 77 youth workers; average age was 38.2 ( SD = 9.8). Significant differences were found between the personal and professional attitudes of TYW concerning cannabis use. No significant difference was found between teachers and youth workers in patterns of use of cannabis or in their professional attitudes. A difference was found between the personal attitudes of teachers and those of youth workers whereby youth workers held more permissive personal attitudes than teachers. A preventive educational program should be constructed to focus on modification of personal and professional attitudes of TYW regarding the subject of cannabis use.

U-shaped curve of psychosis according to cannabis use: New evidence from a snowball sample

BACKGROUND

The aim of this study was to investigate the relationship between psychotic-like experiences (PLEs) assessed using the Community Assessment of Psychic Experience (CAPE) questionnaire and the pattern of cannabis use in a non-clinical sample collected by snowball sampling.

METHODS

Our sample was composed of 204 subjects, distributed into three groups by their cannabis use pattern: 68 were non-cannabis users, 40 were moderate cannabis users and 96 were daily cannabis users. We assessed the psychotic experiences in each group with the CAPE questionnaire; and then controlled for the effect of possible confounding factors like sex, age, social exclusion, age of onset of cannabis use, alcohol use and other drug use.

RESULTS

We found a significant quadratic association between the frequency of cannabis use and positive (β = -1.8; p = 0.004) and negative dimension scores (β = -1.2; p = 0.04). The first-rank and mania factors showed a significant quadratic association (p < 0.05), while the voices factor showed a trend (p = 0.07). Scores for the different groups tended to maintain a U-shape in their values for the different factors. When we adjusted for gender, age, social exclusion, age of onset of cannabis use, and use of alcohol and other drugs, only the first-rank experiences remained significant.

CONCLUSIONS

We found there was a U-shaped curve in the association between cannabis use and the positive and negative dimensions of the CAPE score. We also found this association in mania and first-rank experiences.

Are deficits in cognition associated with psychotic-like experiences after cannabis?

Not all individuals who smoke cannabis report psychotic-like experiences. Given that risk factors for psychotic disorders are multifaceted, precipitating factors to psychotic-like experiences after cannabis are likely to be equally complex. Reduced neurocognitive performance is associated with both psychosis risk and cannabis use. Therefore, it is possible cognitive performance may differentiate those who report psychotic-like experiences after cannabis from those who do not. We determined whether those reporting psychotic/dysphoric experiences after cannabis had reduced neurocognitive performance compared to those reporting primarily euphoric experiences.

METHODS

Participants were recruited on the basis of responses to the cannabis high captured by the Psychosis-Dysphoric and Euphoric experiences subscales from the Cannabis Experiences Questionnaire (CEQ).

RESULTS

Compared to participants reporting primarily euphoric cannabis experiences (n = 36; 44% male; mean age (SD) = 28 (9) years), those who reported psychotic/dysphoric experiences (n = 40; 45% male; mean age (SD) = 26 (5) years) demonstrated significantly faster responses to a trial and error learning task. In the presence of distracters, those with psychotic/dysphoric experiences after cannabis made more errors on a Continuous Performance Task.

CONCLUSIONS

Those who report psychotic/dysphoric experiences after cannabis have subtle inefficiencies in their cognitive processes. The multiple factors which predict vulnerability to psychotic-like experiences after cannabis require further investigation.

Premorbid cannabis use is associated with more symptoms and poorer functioning in schizophrenia spectrum disorder

BACKGROUND

Cannabis use disorder is associated with an earlier age at onset and a more severe outcome of schizophrenia spectrum disorders. The role of cannabis use before the onset of illness (premorbid cannabis use) has not been fully investigated. We here examined how amount and type of premorbid cannabis use was associated with the later course of illness including current substance use, symptoms and level of functioning in schizophrenia spectrum disorder.

METHOD

We used a naturalistic sample of patients with DSM-IV schizophrenia spectrum disorders with a comprehensive history of illness and substance use. Data on premorbid substance use was obtained from comprehensive self-report. The relationship to outcome was investigated using regression models that included current substance use and premorbid functioning.

RESULTS

Pre-schizophrenia cannabis use was significantly associated with more severe psychotic symptoms and impaired functioning. Higher levels of premorbid cannabis use were associated with higher levels of current psychotic symptoms. These associations were independent of current substance use and premorbid functioning. Early use of cannabis (age <17 years) was associated with earlier age at onset of psychosis, independently of potential confounders.

CONCLUSIONS

Pre-psychosis cannabis use affects illness outcome in schizophrenia spectrum disorders, and is associated with lower age at onset of psychosis. These findings of independent negative effects of premorbid cannabis use in schizophrenia suggest that a limitation of the general use of cannabis may have beneficial health effects.

Social media use by physicians: a qualitative study of the new frontier of medicine

Background

A growing number of physicians are using social media as a professional platform for health communication. The purpose of this study was to understand perspectives and experiences of these “early adopter” physician bloggers and social media users.

Methods

This was an exploratory qualitative study involving in-depth semi-structured telephone interviews of physicians who were early adopters, defined as physicians who used social media to distribute health information. Participants were recruited through snowball sampling. Interview transcripts were manually analyzed for common themes by three separate investigators who came to common conclusions via the constant comparative method.

Results

Seventeen physicians participated in this study, including 35 % females, 76 % pediatricians and 76 % bloggers. Participants identified multiple perceived benefits and barriers to social media use by physicians; further, four major themes were identified. First, participants often saw themselves as rugged individualists who set their own rules for social media health communications. Second, participants expressed uncertainty about boundaries or strategies for social media use. Third, participants described using social media much like traditional media, as a one-way communication platform, rather than as an interactive forum. Finally, participants expressed disparate views regarding the time involved in participating in social media; some felt that time spent on social media was unproblematic to fit into their day while others felt that it was an impediment to patient care.

Conclusions

Uncertainty remains regarding roles and responsibilities of physicians providing medical content within social media forums and few providers appeared to be using the platform to its full potential. Future studies may inform best practices to optimize social media health communication to benefit patients.

A virtue analysis of recreational marijuana use

Several empirical studies suggest that recreational marijuana is popularly perceived as an essentially harmless rite of passage that ends as young people settle into their careers and their adult intimate relationships. Is this perception accurate? To answer this question, we evaluate the morality of recreational marijuana use from a virtue perspective guided by the theological synthesis of St. Thomas Aquinas. Since the medical data reveals that recreational marijuana use is detrimental to the well-being of the user, we conclude that it is a vicious activity, an instance of the vice of intoxication, and as such would be morally illicit.

LAY SUMMARY

In contrast to its medical use, the recreational use of marijuana cannot be justified for at least three reasons. First, as scientists have amply documented, it harms the organic functioning of the human body. Second, it impedes our ability to reason and in so doing does harm to us. Finally, it has lasting detrimental effects on the user and his neighbor, even when it occurs in a casual setting. Intoxication is always contrary to the integral good of the person. Thus, the use of marijuana is never warranted even for good, non-medical reasons.

Cannabis psychosis, gender matters

Purpose

– The purpose of this paper is to draw together key literature and analyses of data on admissions for cannabis psychosis in National Health Service hospitals in England (extracted from Hospital Episode Statistics (HES)) to highlight what is known about gender differences in cannabis psychosis and point towards suggestions for improving gender-sensitive treatment and future research.

Design/methodology/approach

– Analysis of British Crime Survey data and HES data were used in combination with data from previously published epidemiological studies to compare gender differences.

Findings

– Male cannabis users outnumber female users by 2:1, a similar gender ratio is found for those admitted to hospital with a diagnosis of schizophrenia or psychosis. However this ratio increases significantly for those admitted to hospital with a diagnosis of cannabis psychosis, with males outnumbering females by 4:1.

Research limitations/implications

– Consistent patterns in gender ratios for people admitted to hospital with cannabis psychosis over a period of 11 years are reported, it is not clear why this gender difference persists but it warrants further investigation which would be aided by improved gender recording at a systemic level.

Practical implications

– This review brings into focus the marked gender differences in cannabis psychosis. Attending to gender is important for research and treatment with the aim of improving understanding and providing gender-sensitive services.

Originality/value

– This paper adds to the literature on gender differences in cannabis psychosis.

Subclinical depressive symptoms and continued cannabis use: predictors of negative outcomes in first episode psychosis

Background

Although depressive symptoms in first episode psychosis have been associated with cannabis abuse, their influence on the long-term functional course of FEP patients who abuse cannabis is unknown. The aims of the study were to examine the influence of subclinical depressive symptoms on the long-term outcome in first episode-psychosis patients who were cannabis users and to assess the influence of these subclinical depressive symptoms on the ability to quit cannabis use.

Methods

64 FEP patients who were cannabis users at baseline were followed-up for 5 years. Two groups were defined: (a) patients with subclinical depressive symptoms at least once during follow-up (DPG), and (b) patients without subclinical depressive symptoms during follow-up (NDPG). Psychotic symptoms were measured using the Positive and Negative Syndrome Scale (PANSS), depressive symptoms using the Hamilton Depression Rating Scale (HDRS)-17, and psychosocial functioning was assessed using the Global Assessment of Functioning (GAF). A linear mixed-effects model was used to analyze the combined influence of cannabis use and subclinical depressive symptomatology on the clinical outcome.

Results

Subclinical depressive symptoms were associated with continued abuse of cannabis during follow-up (β= 4.45; 95% confidence interval [CI]: 1.78 to 11.17; P = .001) and with worse functioning (β = -5.50; 95% CI: -9.02 to -0.33; P = .009).

Conclusions

Subclinical depressive symptoms and continued cannabis abuse during follow-up could be predictors of negative outcomes in FEP patients.

A clinical comparison of schizophrenia with and without pre-onset cannabis use disorder: a retrospective cohort study using categorical and dimensional approaches

BACKGROUND

A high prevalence of cannabis use disorder has been reported in subjects suffering from schizophrenia, fuelling intense debate about whether schizophrenia with pre-onset cannabis use disorder may be a distinct entity with specific features or whether cannabis use disorder can precipitate schizophrenia in genetically vulnerable subjects.

METHODS

We retrospectively assessed schizophrenia subjects with and without pre-onset cannabis use disorder on the basis of their clinical features, assessed categorically and dimensionally with the operational criteria checklist for psychotic illnesses (OCCPI). We also investigated whether the two groups could be differentiated on the basis of a history of psychiatric disorders in first-degree relatives. A principal component factor analysis of the OCCPI items was used to identify specific symptom dimensions. The relationships between symptom dimensions and cannabis status were analysed by point-biserial correlation analysis to control for sex and age at time of the assessment and illness duration.

RESULTS

One hundred and seventy-one subjects with a diagnosis of schizophrenia were included. Among them, forty-one patients (18.2 % of the sample) had a cannabis use disorder before or at the time of the onset of schizophrenia. We found similar results in symptoms patterns or family history between patients with and without pre-onset cannabis use disorder.

CONCLUSIONS

Our results clearly argue against cannabis-associated schizophrenia being a relevant distinct clinical entity of schizophrenia with specific features.

Anxiety mediates the association between cannabis use and attenuated positive psychotic symptoms

Cannabis use has been associated with a continuum of psychotic experiences. However, it is unclear whether mood and anxiety symptoms account for increases in attenuated positive psychotic symptoms (APPS) among cannabis users. We predicted that depression and anxiety symptoms would mediate the relation between cannabis use and APPS, and between cannabis use and endorsement of eight or more distressing APPS (D-APPS), a potentially more clinically meaningful group. Young adults (n=674) completed the Prodromal Questionnaire (PQ); Drug Use Frequency measure; Center for Epidemiologic Studies Depression Scale; State-Trait Anxiety Inventory, Trait Form, Anxiety Subscale; and Social Phobia Scale. Results indicated that symptoms of trait anxiety, but not symptoms of depression or social anxiety, mediated the relationship between cannabis use and APPS, as well as the relationship between cannabis use and D-APPS. Results indicate that symptoms of trait anxiety may play a role in the relation between cannabis use and APPS. Findings underscore the importance of considering clinical characteristics co-occurring with psychotic symptoms, such as affective symptoms, when examining the association between cannabis use and psychotic symptoms.

Impact of Cannabis Use on the Development of Psychotic Disorders

The link between cannabis use and psychosis comprises three distinct relationships: acute psychosis associated with cannabis intoxication, acute psychosis that lasts beyond the period of acute intoxication, and persistent psychosis not time-locked to exposure. Experimental studies reveal that cannabis, tetrahydrocannabinol (THC) and synthetic cannabinoids reliably produce transient positive, negative, and cognitive symptoms in healthy volunteers. Case-studies indicate that cannabinoids can induce acute psychosis which lasts beyond the period of acute intoxication but resolves within a month. Exposure to cannabis in adolescence is associated with a risk for later psychotic disorder in adulthood; this association is consistent, temporally related, shows a dose-response, and is biologically plausible. However, cannabis is neither necessary nor sufficient to cause a persistent psychotic disorder. More likely it is a component cause that interacts with other factors to result in psychosis. The link between cannabis and psychosis is moderated by age at onset of cannabis use, childhood abuse and genetic vulnerability. While more research is needed to better characterize the relationship between cannabinoid use and the onset and persistence of psychosis, clinicians should be mindful of the potential risk of psychosis especially in vulnerable populations, including adolescents and those with a psychosis diathesis.

Cannabis use disorders are comparatively prevalent among nonwhite racial/ethnic groups and adolescents: a national study

The racial/ethnic composition of the US population is shifting, with the nonwhite population growing faster than whites. We examined cannabis use disorder (CUD) prevalences and correlates in seven racial/ethnic groups. We included cannabis use (CU) prevalence as a comparison. Data were from the 2005-2011 National Surveys on Drug Use and Health (N = 394,400). Substance use among respondents aged ≥12 years was assessed by computer-assisted, self-interviewing methods. The following were included as control variables: age, sex, family income, government assistance, county type, residential stability, major depressive episode history, arrest history, nicotine dependence, alcohol disorder, and survey year. Past-year CU prevalence increased significantly from 10.45% in 2005 to 11.41-11.54% during 2009-2011. Compared with whites, mixed-race individuals had higher odds of CU; Asian Americans and Hispanics had lower odds of CU. There were no significant yearly changes in CUD prevalence in the sample during 2005-2011 (1.58-1.73%). Compared with whites, individuals who were mixed-race, black, and Native American had higher odds of CUD; Asian Americans had lower odds. In aggregate, 15.35% of past-year cannabis users met criteria for a CUD in the 12-month period. Past-year cannabis users who were black, Native American, Hispanic, or Asian American had higher odds of CUD than white users. In each racial/ethnic group, adolescent cannabis users generally showed greater odds of CUD than adult users. Behavioral health indicators (major depressive episode, arrest history, nicotine dependence, alcohol disorder) were associated with CU and CUD. In conclusion, CUD disproportionally affects nonwhite groups and youth.

Gone to Pot - A Review of the Association between Cannabis and Psychosis

Cannabis is the most commonly used illicit drug worldwide, with ~5 million daily users worldwide. Emerging evidence supports a number of associations between cannabis and psychosis/psychotic disorders, including schizophrenia. These associations-based on case-studies, surveys, epidemiological studies, and experimental studies indicate that cannabinoids can produce acute, transient effects; acute, persistent effects; and delayed, persistent effects that recapitulate the psychopathology and psychophysiology seen in schizophrenia. Acute exposure to both cannabis and synthetic cannabinoids (Spice/K2) can produce a full range of transient psychotomimetic symptoms, cognitive deficits, and psychophysiological abnormalities that bear a striking resemblance to symptoms of schizophrenia. In individuals with an established psychotic disorder, cannabinoids can exacerbate symptoms, trigger relapse, and have negative consequences on the course of the illness. Several factors appear to moderate these associations, including family history, genetic factors, history of childhood abuse, and the age at onset of cannabis use. Exposure to cannabinoids in adolescence confers a higher risk for psychosis outcomes in later life and the risk is dose-related. Individuals with polymorphisms of COMT and AKT1 genes may be at increased risk for psychotic disorders in association with cannabinoids, as are individuals with a family history of psychotic disorders or a history of childhood trauma. The relationship between cannabis and schizophrenia fulfills many but not all of the standard criteria for causality, including temporality, biological gradient, biological plausibility, experimental evidence, consistency, and coherence. At the present time, the evidence indicates that cannabis may be a component cause in the emergence of psychosis, and this warrants serious consideration from the point of view of public health policy.

Role of Environmental Confounding in the Association between FKBP5 and First-Episode Psychosis

BACKGROUND

Failure to account for the etiological diversity that typically occurs in psychiatric cohorts may increase the potential for confounding as a proportion of genetic variance will be specific to exposures that have varying distributions in cases. This study investigated whether minimizing the potential for such confounding strengthened the evidence for a genetic candidate currently unsupported at the genome-wide level.

METHODS

Two hundred and ninety-one first-episode psychosis cases from South London, UK and 218 unaffected controls were evaluated for a functional polymorphism at the rs1360780 locus in FKBP5. The relationship between FKBP5 and psychosis was modeled using logistic regression. Cannabis use (Cannabis Experiences Questionnaire) and parental separation (Childhood Experience of Care and Abuse Questionnaire) were included as confounders in the analysis.

RESULTS

Association at rs1360780 was not detected until the effects of the two environmental factors had been adjusted for in the model (OR = 2.81, 95% CI 1.23-6.43, p = 0.02). A statistical interaction between rs1360780 and parental separation was confirmed by stratified tests (OR = 2.8, p = 0.02 vs. OR = 0.89, p = 0.80). The genetic main effect was directionally consistent with findings in other (stress-related) clinical phenotypes. Moreover, the variation in effect magnitude was explained by the level of power associated with different cannabis constructs used in the model (r = 0.95).

CONCLUSION

Our results suggest that the extent to which genetic variants in FKBP5 can influence susceptibility to psychosis may depend on other etiological factors. This finding requires further validation in large independent cohorts. Potentially this work could have translational implications; the ability to discriminate between genetic etiologies based on a case-by-case understanding of previous environmental exposures would confer an important clinical advantage that would benefit the delivery of personalizable treatment strategies.