Cannabis-induced psychosis: a cross-sectional comparison with acute schizophrenia

Real world clinical outcomes of treatment of cannabis-induced psychosis and prevalence of cannabis-related primary psychosis: a retrospective study

BACKGROUND

Current treatment of cannabis-induced psychosis (CIP) focus on the presenting symptoms of individual patient. Therefore, the objective of this study was to investigate the efficacy of pharmacological treatment for CIP in a retrospective manner.

METHODS

A retrospective chart review study was conducted at the Princess Mother National Institute on Drug Abuse Treatment (PMNIDAT), Thailand. Patients aged more than 12 years who met the International Classification of Disease-10 (ICD-10) criteria of CIP, had recorded of cannabis use in medical chart, and had positive urine test of cannabis on the first day of admission from October 2013 to September 2019 were enrolled. The primary outcome was the efficacy of pharmacological treatment of CIP. Brief Psychotic Rating Scale (BPRS) on the first day and weekly after receiving treatment were used to assess the primary outcome.

RESULTS

Four hundred and three medical charts with diagnosis of CIP were enrolled into the study and only 317 charts were analyzed. Most of them were male with an average aged of 21.0 (19.0-24.0) years old. All of them used smoked cannabis from dried leaves and flowers of cannabis plant. The presented symptoms on admission were psychosis, mood symptoms, sleep problems, weight loss, and cognitive problems (100%, 64%, 61%, 11%, and 7%, respectively). Baseline BPRS score of the first day of admission was 55.2 ± 9.6. Majority of patients received antipsychotic (98.7%) followed by the combination of antipsychotics with benzodiazepines (34.5.%), antipsychotics with antidepressants (14.4%) and antipsychotics treatment with antidepressants and benzodiazepines (25.9%). Only few patients received antipsychotic monotherapy (17.9%). Risperidone was the most frequently prescribed antipsychotics (83.6%). Mean equivalence dose of risperidone was 8.0 ± 5.9 mg/day. The average hospital length of stay was 28 days (range 22-31). BPRS at 22 days significantly improved compared to the first day of admission (p < 0.001). Schizophrenia was diagnosed in 7% at 1.3 years of follow up.

CONCLUSION

Antipsychotics was still a key psychotropic drug for treatment of CIP. The symptoms were decreased rapidly and sustained among the treatment period. However, antidepressants and benzodiazepines were commonly used for treatment of other symptoms beyond psychosis.

TRIAL REGISTRATION

ClinicalTrials.gov ID: NCT04945031 (Registration Date: 30 June, 2021).

Cannabis use disorder and dissociation: A report from a prospective first-episode psychosis study

BACKGROUND

Cannabis is the most used recreational drug worldwide. Its use can increase the risk of developing psychotic disorders and exacerbate their course. However, the relationship between cannabis use and dissociative symptoms has been scarcely investigated.

AIMS

To examine differences in psychotic and dissociative symptoms, and in functioning in first-episode psychotic patients (FEPp) using cannabis compared with those not using cannabis.

METHODS

Between January 2014 and December 2019, seventy FEPp with cannabis use disorder (N = 35) and without it (N = 35) were recruited in psychiatric inpatient facilities in the Italian regions of Lazio and Piemonte. All subjects were assessed at FEP, after 4 and 8 months, using the Positive and Negative Syndrome Scale (PANSS), the Global Assessment of Functioning (GAF) scale and the Dissociative Experiences Scale - II (DES-II). Detailed information on the pattern of cannabis and other substance use were collected.

RESULTS

FEP using cannabis showed higher levels of positive symptomatology, dissociative experiences and worse functioning than their non-user counterpart, despite a comparable antipsychotic treatment. At an eight-month prospective evaluation, FEP using cannabis still showed higher levels of positive symptomatology and dissociation. Moreover, global functioning worsened over time in FEPp using cannabis, whereas it improved those not using it.

DISCUSSION

Our findings suggest that a greater degree of dissociation and positive symptoms at FEPp and their persistence over time may characterise cannabis-associated psychosis. Both these factors might explain the overall functioning worsening over time that we observed in the cannabis-user group compared to the functioning improvement in the non-user group.

Sociodemographic and clinical profile of cannabis-induced psychosis: A comparative study

BACKGROUND

Cannabis is the most widely used drug in the world. An association between cannabis use and mental illness, in particular psychotic illness, was recognized since long. Various cultures have traditionally used cannabis for different purposes, and continuous increasing use of cannabis is promoting psychosis also.

AIM

The present study has tried to identify the differences in profile between the two groups and thus proposing possible variables underlying cannabis and psychosis.

MATERIALS AND METHODS

This cross-sectional descriptive hospital-based study included 50 consecutive cannabis-using patients with psychosis and equal number of age-matched patients with schizophrenia but no cannabis intake. Permission was taken from the institutional ethics committee. All subjects gave written informed consent. Detailed history regarding psychotic symptoms and different parameters of cannabis use were collected from the key informant as well as the patients in the ward. Both the groups' psychotic symptoms were assessed using scale for assessment of the positive symptoms.

RESULTS

There is no significant difference between both the groups with respect to age. Cannabis-using patients with psychosis showed high symptomatology in the areas of pressure of speech, distractible speech, and clanging. On the other hand, patients with schizophrenia but no cannabis intake showed high symptomatology in the areas of derailment, incoherence, illogicality, and global rating of positive formal thought disorder.

CONCLUSION

Continuous heavy use of cannabis can induce a psychotic disorder distinct from acute schizophrenia. Cannabis-induced psychosis has distinct demographic, premorbid, and clinical features.

Knowledge domain and emerging trends in visual hallucination research: A scientometric analysis

BACKGROUND

Visual hallucination (VH) refers to a spontaneous visual perception without corresponding external stimuli and often occurs in ophthalmological and neuropsychiatric disorders. It is associated with poor quality of life, and increased patient hospitalization and nursing home admission. To date, a scientometric analysis of research on VH is lacking.

AIM

To objectively summarize the features of VH research and gain insights into the emerging trends in research on VH.

METHODS

CiteSpace V was used in this article. Publication outputs, document types, geographic distributions, co-authorship status, research hotspots, and co-citation status were analyzed. A total of 2176 original articles and 465 reviews were included in the database downloaded from the Web of Science Core Collection. We selected the top 50 most cited or occurring articles or items to create a visualized network with a 1-year interval. In the document co-citation analysis stage, we performed clustering analysis on co-cited references, and log likelihood tests were used to name the clusters.

RESULTS

The results showed that most publications can be classified into neurology, sports, and ophthalmology studies. In addition, North America, Europe, Asia and Australia published the most documents. Some well-known authors have always had a leading role in this field; meanwhile, new authors keep emerging. A relatively stable cooperation has been formed among many authors. Furthermore, neuropsychiatric symptom and functional connectivity are the top hotspots. Research on VH in dementia with Lewy bodies and Parkinson’s disease (PD) have received much attention. Studies on VH in PD are likely to be the new emerging trends in the future, especially the mechanisms of VH.

CONCLUSION

Research on VH has formed a complete system. More large-scale clinical and in-depth basic research are required to better understand the mechanisms underlying VH, which will contribute to our understanding of the pathophysiology and therapeutic options for VH.

Recommendations for the medical work-up of first episode psychosis, including specific relevance to Indigenous Australians: A narrative review

AIMS

To collate existing literature for busy practicing psychiatrists about the medical work-up for first-episode psychosis (FEP). Therefore, (a) to review current guidelines for the medical work-up of first episode psychosis. (b) To examine whether any specific recommendations for Indigenous Australians exist. (c) To produce an easy reference table of evidence based investigations.

METHOD

A multi-part narrative review process was undertaken. Step 1 "Source identification and summary": identified key existing national and international guidelines and expert opinions related to the medical work-up of FEP and summarised these suggestions. Step 2 "Exploration of each investigation": examined each of the identified investigations for its importance. Step 3 "Relevance to Indigenous Australians": reviewed any particular relevance to the Indigenous Australian population. Step 4 "Clinician guide": involved presenting recommended investigations in a simple table.

RESULTS

Multiple guidelines were identified. There was clear consensus for many aspects. However, there were also differences in the approach for some investigations. Clinical reasoning for the proposed investigations was commonly absent. There were limited specific recommendations for Indigenous Australians. Evidence and importance was explored for each investigation and auseful table for the practicing psychiatrist was constructed. Investigations were stratified into those considered to be "universal," "low yield," or "unecessary."

CONCLUSION

A narrative review of multiple guidelines relating to the medical work-up of FEP identified many similarities and some differences to their approach. Little additional information exists for the Indigenous Australian context. A clinician friendly worksheet for everyday use may be helpful to busy clinicians.

Catatonia Related to Cannabis and Synthetic Cannabinoids: A Review

Cannabis and synthetic cannabinoids (SC) are related to several neuropsychiatric symptoms and disorders, especially psychotic symptoms and disorders. Interestingly, catatonia-like symptoms associated with cannabis and SC have been generally neglected in research and scarcely described despite the clinical repercussions. Hence, this review aims to analyze current clinical publications on catatonia induced by cannabis or SC in a systematized way. Methods: A search using PRISMA guidelines was performed on three databases based on a specific inclusion and exclusion criteria. Results: 11 publications describing 14 patients (10 males; mean age 22.50 ± 6.67 years old) with catatonia apparently precipitated by the use of cannabis (n = 6) or SC (n = 8) were found. Clinical features and treatment are described and discussed. Conclusion: From a clinical perspective, cannabis and SC use may be related to catatonia-like symptoms and catatonia syndrome in the same way these substances (cannabis and SC) are related to induced-psychotic episodes. However, further research will be required to understand the exact nature of that relationship. Additionally, investigations focused on the clinical significance (i.e., prognosis, evolution, and outcomes) of catatonia-like symptoms induced by cannabis and SC use in patients are also needed.

Endocannabinoid-serotonin systems interaction in health and disease

Endocannabinoid (eCB) and serotonin (5-HT) neuromodulatory systems work both independently and together to finely orchestrate neuronal activity throughout the brain to strongly sculpt behavioral functions. Surprising parallelism between the behavioral effects of 5-HT and eCB activity has been widely reported, including the regulation of emotional states, stress homeostasis, cognitive functions, food intake and sleep. The distribution pattern of the 5-HT system and the eCB molecular elements in the brain display a strong overlap and several studies report a functional interplay and even a tight interdependence between eCB/5-HT signaling. In this review, we examine the available evidence of the interaction between the eCB and 5-HT systems. We first introduce the eCB system, then we describe the eCB/5-HT crosstalk at the neuronal and synaptic levels. Finally, we explore the potential eCB/5-HT interaction at the behavioral level with the implication for psychiatric and neurological disorders. The precise elucidation of how this neuromodulatory interaction dynamically regulates biological functions may lead to the development of more targeted therapeutic strategies for the treatment of depressive and anxiety disorders, psychosis and epilepsy.

Psychosis-Relevant Effects of Intravenous Delta-9-Tetrahydrocannabinol: A Mega Analysis of Individual Participant-Data from Human Laboratory Studies

INTRODUCTION

There is increasing interest in the relationship between cannabinoids and psychosis. While individual human laboratory studies have been critical in demonstrating that cannabinoids (e.g., delta-9-tetrahydrocannabinol [THC]) can induce acute transient psychosis-like effects in healthy human volunteers, combining data from multiple studies offers a fine-grained view of these effects.

METHODS

THC-induced psychosis-relevant effects were examined using a data repository of 10 double-blind, randomized, placebo-controlled, crossover studies with 400 i.v. THC infusions in healthy human volunteers. The Positive and Negative Syndrome scale was used to measure psychotomimetic effects. The profile of symptoms, frequency of a response, its relationship to THC dose and substance use, latent structure in Positive and Negative Syndrome scale response, and the relationships between psychotomimetic and perceptual alteration symptoms were evaluated.

RESULTS

Clinically meaningful increases in positive symptoms were noted in 44.75% infusions; conceptual disorganization, hallucinations, blunted affect, somatic concern, motor retardation, and poor attention were the items most frequently altered by THC. The increase in Positive and Negative Syndrome scale positive symptoms was positively associated with THC dose (beta = 11.13, SE = 4.94, Wald χ 2 = 19.88, P < .001) and negatively associated with frequent cannabis use (beta = -0.575, SE = 0.14, Wald χ 2 = 18.13, P < .001). Furthermore, positive symptoms were strongly correlated with Clinician Administered Dissociative States Scale perceptual alterations score (rs = 0.514, P < .001).

CONCLUSION

Intravenous administration of THC consistently induces psychotomimetic effects that include symptoms across Positive and Negative Syndrome scale domains. Moreover, healthy individuals who frequently use cannabis have a blunted psychotomimetic response.

Characteristics and outcomes of young people with substance induced psychotic disorder

BACKGROUND

Substance induced psychotic disorders (SIPD) have been historically considered as associated with better clinical and functional outcomes than other psychotic diagnoses. As a result, treatments for those with SIPD are often considerably less intensive, yet this is not based on evidence. The present study aimed to examine whether differences exist between those with SIPD and other first episode psychosis (FEP) diagnoses in regards to demographic and clinical factors, and to determine the symptomatic, clinical and functional outcomes in those with SIPD.

METHODS

This study included all young people aged 15-24 who presented with a FEP to the Early Psychosis Prevention and Intervention Centre between 01/01/2011 and 31/12/2013. Group differences were analysed with independent samples t-tests and chi-square analyses and equivalent non-parametric tests as appropriate. Where applicable, odds ratios were calculated.

RESULTS

544 young people presented with a FEP and 10.3% (N = 56) were diagnosed with SIPD. Individuals with SIPD were more likely to be male, unemployed, and have a comorbid substance use disorder. There were no significant differences between groups regarding duration of untreated psychosis, severity of psychotic symptoms, time to remission, or rates of relapse. Those with SIPD were less likely to be employed or engaged in study at discharge and 35.7% of those with SIPD had a change of diagnosis to a schizophrenia spectrum or bipolar disorder after a median of 84 weeks.

CONCLUSION

Young people diagnosed with SIPD should be an important focus of early intervention services and receive comparable treatment to those with other psychotic diagnoses.

Cannabis induced psychosis and subsequent psychiatric disorders

INTRODUCTION

Long term change in diagnosis of patients having Cannabis induced psychosis (CIP) at the index evaluation is well recognised. Some patients are known to achieve complete remission while others go on to develop independent schizophrenia or mood disorders.

AIMS

To study the long-term course of CIP and factors influencing it.

METHOD

Patients diagnosed as CIP (ICD 10: F12.5), admitted at NIMHANS, a tertiary neuropsychiatry centre at Bangalore, over the past 10 years were identified from medical records. 200 case records were identified and screened in detail. 57 met inclusion criteria and 35 patients could be followed up. Mean follow up duration was 5.75 years.

RESULTS

Patients who completely abstained from cannabis after the 1^st episode had no relapse of psychiatric illness. They showed marked improvement in socio-occupational functioning as well. All those who relapsed to cannabis use had a recurrence of illness. Half the patients with predominantly non-affective psychosis progressed to an independent psychiatric disorder; while only 7.7% patients with predominantly affective psychosis developed an independent disorder (p=0.01). Besides this, early onset of cannabis use (≤18years), younger age at onset of 1st episode, positive family history of psychiatric illness, being unmarried and lower socio-economic status were associated with poor prognosis. Abstinence later in the course of illness did not improve outcome significantly.

CONCLUSION

Abstaining from cannabis early in the course of illness is critical for good recovery. The course of CIP is variable and categorising CIP into affective vs. non-affective psychosis can be useful in clinical practice.

Endo-cannabinoids system and the toxicity of cannabinoids with a biotechnological approach

Cannabinoids have shown diverse and critical effects on the body systems, which alter the physiological functions. Synthetic cannabinoids are comparatively innovative misuse drugs with respect to their nature of synthesis. Synthetic cannabinoids therapy in healthy, chain smokers, and alcoholic individuals cause damage to the immune and nervous system, eventually leading to intoxication throughout the body. Relevant studies were retrieved using major electronic databases such as PubMed, EMBASE, Medline, Scopus, and Google Scholar. The extensive use of Cannabis Sativa L. (C. Sativa) and its derivatives/analogues such as the nonpsychoactive dimethyl heptyl homolog (CBG-DMH), and tetrahydrocannabivarin (THCV) amongst juveniles and adults have been enhanced in recent years. Cannabinoids play a crucial role in the induction of respiratory, reproductive, immune and carcinogenic effects; however, potential data about mutagenic and developmental effects are still insufficient. The possible toxicity associated with the prolong use of cannabinoids acts as a tumor promoter in animal models and humans. Particular synthetic cannabinoids and analogues have low affinity for CB1 or CB2 receptors, while some synthetic members like Δ9-THC have high affinity towards these receptors. Cannabinoids and their derivatives have a direct or indirect association with acute and long-term toxicity. To reduce/attenuate cannabinoids toxicity, pharmaceutical biotechnology and cloning methods have opened a new window to develop cannabinoids encoding the gene tetrahydrocannabinolic acid (THCA) synthase. Plant revolution and regeneration hindered genetic engineering in C. Sativa. The genetic culture suspension of C. Sativa can be transmuted by the use of Agrobacterium tumefaciens to overcome its toxicity. The main aim of the present review was to collect evidence of the endo-cannabinoid system (ECS), cannabinoids toxicity, and the potential biotechnological approach of cannabinoids synthesis.

Short-term outcome of substance-induced psychotic disorder in a large UK first episode psychosis cohort

OBJECTIVE

The incidence and outcome of first-episode substance-induced psychotic disorder (SIPD) are unclear. The study aimed to compare the 1-year outcomes of those given a SIPD diagnosis by clinicians compared to other psychosis diagnoses in a first-episode cohort.

METHOD

Data were from a large (n = 1027) cohort of first-episode psychosis (FEP) patients admitted to early intervention services in the UK (National EDEN). Diagnosis, including that of SIPD, was made by treating psychiatrists at baseline using ICD10 criteria. Details on symptoms, functioning, quality of life, relapse and recovery were available at baseline and 12 months.

RESULTS

There were 67 cases of SIPD (6.5% of the cohort). At baseline, SIPD patients were no different to other psychoses on symptoms, functioning and quality of life. At 12 months, there was no difference in SIPD and other psychoses on functioning, quality of life or relapse and recovery rates. Levels of psychotic and general symptomatology were similar but depressive symptoms were higher in the SIPD group.

CONCLUSIONS

First-episode psychosis patients with a diagnosis of SIPD do not appear to have better outcomes than those with other primary psychotic diagnoses. The higher levels of depressive symptoms may be a specific marker in these patients.

Long-term risk factors for substance-induced and primary psychosis after release from prison. A longitudinal study of substance users

PURPOSE

The purpose of this study was to determine long-term risk factors for substance-induced and primary psychosis after release from prison.

MATERIAL

We used a longitudinal register-based cohort study combining European version of Addiction Severity Index (Europ-ASI) interviews and the Swedish inpatient register. The study included 6217 individuals who were in the Swedish criminal justice system from 2001 to 2006.

MEASUREMENTS

The outcomes were substance-induced and primary psychosis as defined by the International Classification of Disease - 10th version. All variables for estimating baseline risk were drawn from the Europ-ASI interview, and included information on substance use, demographics and health. The interview database and the inpatient register were coupled, and groups were compared by using tests of significance and logistic regression.

RESULTS

Polydrug use was the strongest predictor for substance induced psychosis (OR=9.55, 95% CI 3.42-26.67), but all substances imposed an increased risk. Previous psychiatric hospitalization and non-drug related hallucinations were significant, but weaker, risk factors. The only substance variable that predicted primary psychosis was cannabis (OR=2.62, 95% CI 1.39-4.96), but previous psychiatric hospitalization (OR=3.22, 95% CI 2.27-4.54) and non-drug related hallucinations (OR=4.00, 95% CI 2.82-5.67) were even stronger predictors.

CONCLUSIONS

Cannabis use was a risk factor for primary psychosis, but other health related individual risk factors were even more important. Polydrug use was the strongest risk factor for substance-induced psychosis.

Atypical course in severe catatonic schizophrenia in a cannabis-dependent male adolescent: a case report

INTRODUCTION

Adolescents with psychoses usually have full recovery from their first psychotic episode, but the first relapse often arises within 2 years of the first episode. Cannabis-related psychoses are difficult to distinguish from schizophrenic psychoses. Here, we describe a particularly severe clinical case, with a first psychotic episode occurring after heavy cannabis smoking, an atypically long symptom-free duration, and a subsequent non-substance-related episode.

CASE PRESENTATION

A 17-year-old male adolescent of Middle-East origin presented with delusions and hallucinations after extensive cannabis smoking. His first psychotic episode, with paranoid delusions and hallucinations, progressed into severe catatonic symptoms. His symptoms were treated with electroconvulsive therapy and risperidone and he was transferred to a residential substance abuse treatment center. He remained drug-free and non-psychotic for 3.5 years. Given the temporal association with extensive cannabis use, and his full remission of symptoms lasting several years, a cannabis-induced psychosis-though atypically extended-could be suspected. However, after 3.5 years without psychiatric care, and in a drug-free state, our patient again presented with positive psychotic symptoms, possibly induced by a period of severe psychosocial stress.

CONCLUSION

We here discuss whether a primary schizophrenic episode possibly induced by cannabis can increase the risk of subsequent non-drug-related schizophrenic episodes.

Characterizing cannabis-induced psychosis: a study with prepulse inhibition of the startle reflex

Cannabis-induced psychotic disorder (CIPD) refers to psychotic symptoms that arise in the context of cannabis intoxication. Prepulse inhibition (PPI) deficits have been extensively identified in schizophrenia and in cannabis abusers. We aimed to characterize PPI in CIPD patients. We used a sample of 48 CIPD patients, 54 schizophrenia patients and cannabis abuse (SCHZ), 44 cannabis dependents (CD), and 44 controls. CIPD, SCHZ and CD were abstinent of cannabis consumption for 9 months. Participants were assessed with PPI at 30, 60, and 120 ms. At 30 ms, CIPD showed lower PPI levels than controls, and SCHZ obtained worse functioning than controls and CD. At 60 ms, only SCHZ exhibited worse PPI percentages (of object) than controls. Finally, at 120 ms, CIPD showed higher PPI levels than SCHZ, and SCHZ obtained lower percentages than controls. We found that CIPD and SCHZ patients showed deficits at the most pre-attentional levels, whereas CIPD patients performed better than SCHZ at higher attentional levels. These results suggest that CIPD constitutes a different group of patients than that of SCHZ. Deficits in PPI functioning at 30 ms could be a useful psychophysiological measure to detect CIPD patients, who are frequently confused with cannabis abusers whose symptoms may mimic that of schizophrenia.

Acute influence of alcohol, THC or central stimulants on violent suicide: A Swedish population study

Alcohol and substance abuse in general is a risk factor for suicide, but very little is known about the acute effect in relation to suicide method. Based on information from 18,894 medico-legal death investigations, including toxicological findings and manner of death, did the present study investigate whether acute influence of alcohol, tetrahydrocannabinol (THC), or central stimulants (amphetamine and cocaine) was related to the use of a violent suicide method, in comparison with the nonviolent method self-poisoning and alcohol-/illicit drug-negative suicide decedents. Multivariate analysis was conducted, and the results revealed that acute influence of THC was related to using the violent suicide method–– jumping from a height (RR 1.62; 95% CI 1.01–2.41). Alcohol intoxication was not related to any violent method, while the central stimulant-positive suicide decedent had a higher, albeit not significant, risk of several violent methods. The study contributes with elucidating suicide methods in relation to acute intoxication.

Cannabis and schizophrenia

BACKGROUND

Schizophrenia is a mental illness causing disordered beliefs, ideas and sensations. Many people with schizophrenia smoke cannabis, and it is unclear why a large proportion do so and if the effects are harmful or beneficial. It is also unclear what the best method is to allow people with schizophrenia to alter their cannabis intake.

OBJECTIVES

To assess the effects of specific psychological treatments for cannabis reduction in people with schizophrenia.To assess the effects of antipsychotics for cannabis reduction in people with schizophrenia.To assess the effects of cannabinoids (cannabis related chemical compounds derived from cannabis or manufactured) for symptom reduction in people with schizophrenia.

SEARCH METHODS

We searched the Cochrane Schizophrenia Group Trials Register, 12 August 2013, which is based on regular searches of BIOSIS, CINAHL, EMBASE, MEDLINE, PUBMED and PsycINFO.We searched all references of articles selected for inclusion for further relevant trials. We contacted the first author of included studies for unpublished trials or data.

SELECTION CRITERIA

We included all randomised controlled trials involving cannabinoids and schizophrenia/schizophrenia-like illnesses, which assessed:1) treatments to reduce cannabis use in people with schizophrenia;2) the effects of cannabinoids on people with schizophrenia.

DATA COLLECTION AND ANALYSIS

We independently inspected citations, selected papers and then re-inspected the studies if there were discrepancies, and extracted data. For dichotomous data we calculated risk ratios (RR) and for continuous data, we calculated mean differences (MD), both with 95% confidence intervals (CI) on an intention-to-treat basis, based on a fixed-effect model. We excluded data if loss to follow-up was greater than 50%. We assessed risk of bias for included studies and used GRADE to rate the quality of the evidence.

MAIN RESULTS

We identified eight randomised trials, involving 530 participants, which met our selection criteria.For the cannabis reduction studies no one treatment showed superiority for reduction in cannabis use. Overall, data were poorly reported for many outcomes of interest. Our main outcomes of interest were medium-term data for cannabis use, global state, mental state, global functioning, adverse events, leaving the study early and satisfaction with treatment. 1. Reduction in cannabis use: adjunct psychological therapies (specifically about cannabis and psychosis) versus treatment as usualResults from one small study showed people receiving adjunct psychological therapies specifically about cannabis and psychosis were no more likely to reduce their intake than those receiving treatment as usual (n = 54, 1 RCT, MD -0.10, 95% CI -2.44 to 2.24, moderate quality evidence). Results for other main outcomes at medium term were also equivocal. No difference in mental state measured on the PANSS positive were observed between groups (n = 62, 1 RCT, MD -0.30 95% CI -2.55 to 1.95, moderate quality evidence). Nor for the outcome of general functioning measured using the World Health Organization Quality of Life BREF (n = 49, 1 RCT, MD 0.90 95% CI -1.15 to 2.95, moderate quality evidence). No data were reported for the other main outcomes of interest 2. Reduction in cannabis use: adjunct psychological therapy (specifically about cannabis and psychosis) versus adjunct non-specific psychoeducation One study compared specific psychological therapy aimed at cannabis reduction with general psychological therapy. At three-month follow-up, the use of cannabis in the previous four weeks was similar between treatment groups (n = 47, 1 RCT, RR 1.04 95% CI 0.62 to 1.74, moderate quality evidence). Again, at a medium-term follow-up, the average mental state scores from the Brief Pscychiatric Rating Scale-Expanded were similar between groups (n = 47, 1 RCT, MD 3.60 95% CI - 5.61 to 12.81, moderate quality evidence). No data were reported for the other main outcomes of interest: global state, general functioning, adverse events, leaving the study early and satisfaction with treatment. 3. Reduction in cannabis use: antipsychotic versus antipsychotic In a small trial comparing effectiveness of olanzapine versus risperidone for cannabis reduction, there was no difference between groups at medium-term follow-up (n = 16, 1 RCT, RR 1.80 95% CI 0.52 to 6.22, moderate quality evidence). The number of participants leaving the study early at medium term was also similar (n = 28, 1 RCT, RR 0.50 95% CI 0.19 to 1.29, moderate quality evidence). Mental state data were reported, however they were reported within the short term and no difference was observed. No data were reported for global state, general functioning, and satisfaction with treatment.With regards to adverse effects data, no study reported medium-term data. Short-term data were presented but overall, no real differences between treatment groups were observed for adverse effects. 4. Cannabinoid as treatment: cannabidiol versus amisulprideAgain, no data were reported for any of the main outcomes of interest at medium term. There were short-term data reported for mental state using the BPRS and PANSS, no overall differences in mental state were observed between treatment groups.

AUTHORS' CONCLUSIONS

Results are limited and inconclusive due to the small number and size of randomised controlled trials available and quality of data reporting within these trials. More research is needed to a) explore the effects of adjunct psychological therapy that is specifically about cannabis and psychosis as currently there is no evidence for any novel intervention being better than standard treatment,for those that use cannabis and have schizophrenia b) decide the most effective drug treatment in treating those that use cannabis and have schizophrenia, and c) assess the effectiveness of cannabidiol in treating schizophrenia. Currently evidence is insufficient to show cannabidiol has an antipsychotic effect.

Summary of evidence-based guideline: complementary and alternative medicine in multiple sclerosis: report of the guideline development subcommittee of the American Academy of Neurology

OBJECTIVE

To develop evidence-based recommendations for complementary and alternative medicine (CAM) in multiple sclerosis (MS).

METHODS

We searched the literature (1970-March 2011; March 2011-September 2013 MEDLINE search), classified articles, and linked recommendations to evidence.

RESULTS AND RECOMMENDATIONS

Clinicians might offer oral cannabis extract for spasticity symptoms and pain (excluding central neuropathic pain) (Level A). Clinicians might offer tetrahydrocannabinol for spasticity symptoms and pain (excluding central neuropathic pain) (Level B). Clinicians should counsel patients that these agents are probably ineffective for objective spasticity (short-term)/tremor (Level B) and possibly effective for spasticity and pain (long-term) (Level C). Clinicians might offer Sativex oromucosal cannabinoid spray (nabiximols) for spasticity symptoms, pain, and urinary frequency (Level B). Clinicians should counsel patients that these agents are probably ineffective for objective spasticity/urinary incontinence (Level B). Clinicians might choose not to offer these agents for tremor (Level C). Clinicians might counsel patients that magnetic therapy is probably effective for fatigue and probably ineffective for depression (Level B); fish oil is probably ineffective for relapses, disability, fatigue, MRI lesions, and quality of life (QOL) (Level B); ginkgo biloba is ineffective for cognition (Level A) and possibly effective for fatigue (Level C); reflexology is possibly effective for paresthesia (Level C); Cari Loder regimen is possibly ineffective for disability, symptoms, depression, and fatigue (Level C); and bee sting therapy is possibly ineffective for relapses, disability, fatigue, lesion burden/volume, and health-related QOL (Level C). Cannabinoids may cause adverse effects. Clinicians should exercise caution regarding standardized vs nonstandardized cannabis extracts and overall CAM quality control/nonregulation. Safety/efficacy of other CAM/CAM interaction with MS disease-modifying therapies is unknown.

Psychosis following chloroquine ingestion: a 10-year comparative study from a malaria-hyperendemic district of India

OBJECTIVES

Serious adverse effects such as acute psychoses have been reported following treatment with chloroquine. Chloroquine can cause cell death, including neurons. We aimed to identify the most frequent type of psychiatric manifestation and symptomatological characteristics of psychosis following chloroquine ingestion (PFC).

METHOD

Out of a total of 4471 randomly selected recent-onset psychosis patients, 3610 consecutive patients who had responded to standard treatment were screened for entry in the study. We compared background clinicodemographic profile information and psychopathology of 51 PFC patients, who were either drug free or drug naive, to 51 brief psychotic disorder (BPD) patients who were matched in terms of age, sex and education. Only those patients who remitted within 8 weeks (PFC patients) or 4 weeks (BPD patients) were included. Cranial computed tomography, electroencephalography and lumbar puncture of the entire experimental group were normal, and none had Mini Mental Status Examination score <22. Group difference and correlational statistics (parametric and nonparametric) have been used to test the hypotheses and explain the results.

RESULTS

The most common (76.2%) type of psychiatric disturbance in PCF group was mood disorder (mixed episode) accompanied by predominant irritability with little blunting of affect. PFC patients characteristically had prominent positive symptoms with visual hallucination and derealization experiences. They were more restless, agitated and anxious and had more disturbed thought content and orientation, but better preserved insight. There was no linear relationship between the amount of chloroquine consumed and the severity of psychosis.

CONCLUSION

Considering the large number of patients still receiving chloroquine especially in developing countries, this study has been presented to draw attention of the psychiatrists and other health professionals to the hazardous effect of chloroquine on mental health.

Aripiprazole for treating cannabis-induced psychotic symptoms in ultrahigh-risk individuals

Cannabis-induced psychotic symptoms (CIPSs) have both similarities and differences with positive symptoms of schizophrenia, and it remains unclear whether CIPSs result from dopaminergic mechanisms and can be treated with antipsychotics. We report the case of a 22-year-old male patient with ultrahigh risk criteria for psychosis, who reported cannabis addiction and recurrent CIPSs. Aripiprazole 10 mg/d could totally and durably suppress CIPSs in the patient, but had no effect on the smoking level. Treating CIPSs in ultrahigh risk individuals who cannot stop or refuse stopping cannabis might fit a harm-reduction strategy by preventing transition into psychosis.

Psychopathologic differences between cannabis-induced psychoses and recent-onset primary psychoses with abuse of cannabis

The study aims to identify psychopathologic variables in cannabis-induced psychosis and recent-onset primary psychoses using the Symptom Checklist-90-R and the Psychiatric Research Interview for Substance and Mental Disorders. A sample of 181 subjects with psychotic symptoms and cannabis use referred to the psychiatry inpatient units of 3 university general hospitals were assessed. The final sample included 50 subjects with a diagnosis of cannabis-induced psychotic disorder (CIPD) and 104 subjects with primary psychotic disorders. Using receiver operating characteristic curves, the most efficient psychopathologic variables for classifying CIPD were interpersonal sensitivity, "depression," phobic anxiety, and Scale to Assess Unawareness of Mental Disorders subscales. The area under the receiver operating characteristic curve of the model including depression and "misattribution" scores was 96.78% (95% confidence interval, 94.43-99.13). Depressive symptoms could be used to distinguish CIPD from other primary psychotic disorders. Clinical variables related to "neurotic" symptoms could be involved in the susceptibility to cannabis-induced psychosis.

Plasma Endocannabinoid Alterations in Individuals with Substance Use Disorder are Dependent on the "Mirror Effect" of Schizophrenia

Schizophrenia is a complex psychiatric disorder strongly associated with substance use disorders. Theoretically, schizophrenia and SUD may share endocannabinoid alterations in the brain reward system. The main endocannabinoids, anandamide, and 2-arachidonoylglycerol, are lipids which bind cannabinoid receptors. Oleoylethanolamide (OEA), a fatty-acid ethanolamide, binds peroxisome proliferator-activated receptors. The endocannabinoid system has been shown to be impaired in schizophrenia, and recently, our group has shown that schizophrenia patients with SUD have elevated peripheral levels of anandamide and OEA that do not normalize after 3-month treatment with quetiapine. Objective For comparative purposes, we aimed to measure endocannabinoids in non-psychosis substance abusers and non-abusing schizophrenia patients. Methods Using liquid chromatography and mass spectrometry, we measured plasma levels of anandamide and OEA in non-psychosis SUD patients, non-abusing schizophrenia patients, and healthy controls. In an open-label manner, all patients received 12-week treatment with quetiapine. Results Anandamide and OEA were reduced in substance abusers without schizophrenia, relative to healthy controls (p < 0.05). Both endocannabinoids were unchanged in non-abusing schizophrenia patients. After quetiapine, anandamide, and OEA levels remained significantly reduced the SUD group (p < 0.05). Discussion Taken together with results of our previous study performed in dual-diagnosis patients, our results suggest that peripheral anandamide and OEA levels are impaired in patients with SUD in opposite ways according to the presence or absence of schizophrenia. Endocannabinoid alterations did not change with treatment, suggesting that they are trait markers. Further studies are necessary to understand the role of endocannabinoids in substance abusers with and without schizophrenia and to examine therapeutic implications.

Psychopharmacological comparison of schizophrenia spectrum disorder with and without cannabis dependency

BACKGROUND

Although incidence of schizophrenia is higher among cannabis users and marijuana is the most common abused drug by adolescents, etiological linkage between schizophrenia and cannabis use is still not clarified. Clinical experiences suggest that regular cannabis user can show similar psychotic episode to schizophrenic disorders but it is still unclear if chronic cannabis use with schizophreniform disorder is a distinct entity requiring special therapy or it can be treated as classical schizophrenia. There are no data available on the comparison of pharmacotherapy between schizophreniform patients with and without cannabis use.

METHODS

Clinical data of 85 patients with schizophrenia spectrum disorder were analyzed retrospectively. Cannabis use was not reported by 43 persons (Cnbs0 subgroup) and 42 patients used regularly cannabis during at least 1 year (Cnbs1 subgroup). Comparison of anamnesis, family history, social-demographic condition, positive and negative symptoms, acute and long-term therapies recorded by clinical interviews was performed with chi square tests, logistic binary regression and t-tests using SPSS 13.0 for Windows software.

RESULTS

Men were over-represented in cannabis dependent group while mean age was lower among them compared to Cnbs0 subgroup. Prevalence of suicidal attempt was increased in men without cannabis use (OR = 5.25, p = 0.016). Patients without cannabis use spent more time in hospital (p = 0.026) and smoking was more frequent among them (OR = 1.36, p = 0.047). The chance to get olanzapine for acute therapy and aripiprazol for long term therapy was more than two fold in Cnbs1 subgroup (OR = 2.66, OR = 3.67, respectively). However, aripiprazol was used for acute therapy with significantly lower risk in Cnbs1 subgroup (OR = 0.47, p = 0.023). Olanzapine was administered for long term therapy in a higher dose to Cnbs0 patients (p = 0.040). Also higher dose of risperidon LAI was used in women without cannabis dependency compared to women of Cnbs1 subgroup (p=0.020). Positive and negative symptoms and family history did not differ significantly between the two subgroups.

CONCLUSION

Although symptom profile was similar, hospitalization time, suicidal anamnesis, smoking habit and also dosage, intensity and lasting of therapy were different between the two subgroups. Further prospective studies are required for the investigation of the clinical and molecular background of this discrepancy in order to determine a relevant protocol of prevention and treatment of the chronic cannabis use related psychotic disorder.

Endocannabinoids and Schizophrenia

The endocannabinoids anandamide and 2-arachydonoylglycerol (2-AG) are lipids naturally derived from membrane precursors which bind cannabinoid receptors (CB₁, CB₂). This endocannabinoid system is disturbed in schizophrenia. Indeed, there seems to be an association between schizophrenia and polymorphisms of the CB₁ receptor gene. Moreover, CB₁ receptors are found in higher density in the prefrontal cortex, hippocampus and basal ganglia of patients with schizophrenia. Similarly, anandamide levels are increased in the cerebrospinal fluid (CSF) and in the serum of schizophrenia patients, including during the prodromal state, suggesting that they may play a protective role in psychosis homeostasis. Future studies are needed to further explore the role of the endocannabinoid system in the pathophysiology of schizophrenia.

[Cannabis and mood]

OBJECTIVE

Evaluate the relationship between acute and chronic use of cannabis and mood changes.

METHOD

Articles were selected by electronic search in PubMed. Chapters in books and reference lists of selected articles were also reviewed. As the research did not involve humans, there was no evaluation by a Research Ethics Committee.

RESULTS

High rates of comorbidity between use/abuse/dependence of cannabis and affective disorders in longitudinal studies and in clinical samples were observed. Longitudinal studies indicate that, in long-term, the higher use of cannabis is associated with an increased risk of developing bipolar disorder, and probably, major depression in subjects initially without affective disorder, but was not found increased risk of cannabis use among those initially only with mania or depression. Another important observation is that substance abuse in bipolar patients may be associated with a number of negative characteristics, such as difficulty in recovering the affective symptoms, more hospitalizations, poor compliance with treatment, increased risk of suicide, aggression and a poor response to lithium. Psychosocial and pharmacological treatments are indicated for the management of comorbidity between cannabis and affective disorders.

CONCLUSION

The relationship between cannabis use and mood changes are observed both in the epidemiological research and in the clinical settings.

A retrospective analysis of cannabis use in a cohort of mentally ill patients in Sri Lanka and its implications on policy development

BACKGROUND

Several epidemiological studies have shown that cannabis; the most widely used illegal drug in the world, is associated with schizophrenia spectrum disorders (SSD).

AIMS

To assess the characteristics of cannabis use and its association with SSD in a cohort of psychiatrically ill patients and discuss the implications for policy development

METHODS

This is a retrospective analytical study of a cohort of psychiatric patients who received treatment in the psychiatry unit of the Provincial General Hospital, Ratnapura, Sri Lanka over five years (2000 - 2004). The schizophrenia spectrum disorders defined in this article include schizophrenia and the schizoaffective disorders.

RESULTS

A total of 3644 patient records were analyzed. The percentage of self reported life time cannabis (LTC) use was 2.83% (103, all males). Sixteen percent (576) of the total cohort was diagnosed with SSD by 2009. Male sex and LTC use were significantly associated with SSD (p < 0.01 and 0.001 respectively). In the majority (91.5%), cannabis use preceded the diagnosis. There were 17(16.5%) patients diagnosed as cannabis induced psychosis and 7 (41.2%) of them were subsequently diagnosed as SSD. This group was significantly more likely to have had a past psychiatric consultation, but other demographic and clinical correlates did not differ from the rest of the LTC users.

CONCLUSIONS

Self reported LTC use was strongly associated with being diagnosed with SSD. However we could not identify a particular subgroup of users that are at increased risk to recommend targeted primary prophylaxis. The policy implications of this observation are discussed.

Role of cannabis and endocannabinoids in the genesis of schizophrenia

RATIONALE

Cannabis abuse and endocannabinoids are associated to schizophrenia.

OBJECTIVES

It is important to discern the association between schizophrenia and exogenous Cannabis sativa, on one hand, and the endogenous cannabinoid system, on the other hand.

RESULTS

On one hand, there is substantial evidence that cannabis abuse is a risk factor for psychosis in genetically predisposed people, may lead to a worse outcome of the disease, or it can affect normal brain development during adolescence, increasing the risk for schizophrenia in adulthood. Regarding genetic predisposition, alterations affecting the cannabinoid CNR1 gene could be related to schizophrenia. On the other hand, the endogenous cannabinoid system is altered in schizophrenia (i.e., increased density of cannabinoid CB1 receptor binding in corticolimbic regions, enhanced cerebrospinal fluid anandamide levels), and dysregulation of this system can interact with neurotransmitter systems in such a way that a "cannabinoid hypothesis" can be integrated in the neurobiological hypotheses of schizophrenia. Finally, there is also evidence that some genetic alterations of the CNR1 gene can act as a protectant factor against schizophrenia or can induce a better pharmacological response to atypical antipsychotics.

CONCLUSIONS

Cannabis abuse is a risk factor for psychosis in predisposed people, it can affect neurodevelopment during adolescence leading to schizophrenia, and a dysregulation of the endocannabinoid system can participate in schizophrenia. It is also worth noting that some specific cannabinoid alterations can act as neuroprotectant for schizophrenia or can be a psychopharmacogenetic rather than a vulnerability factor.

Cannabis and schizophrenia spectrum disorders: a review of clinical studies

Cannabis is the most widely used illegitimate substance in the world, and the number of users has increased by 10% over the last decade worldwide. Therefore, it is important to review the evidence on psychoactive properties of cannabis and its possible association with schizophrenia spectrum disorders (SSD). We searched MEDLINE with the key words cannabis and schizophrenia. The search was limited to articles published in English over the last 10 years (1999-2009). Bibliographies of cited literature were also searched. Data sources included reviews published in core clinical journals, cohort studies, interventional studies, case-control studies, cross-sectional analyses and epidemiological data. Results are discussed under 2 topics. Firstly, evidence related to biochemical functioning of cannabinoids and their relationship to endocannabinoid system is discussed briefly. Secondly, the evidence from clinical studies on cannabis, psychosis proneness and SSD are discussed in detail. The discussion is structured to fit in the evidence from results section to 3 plausible hypotheses on cannabis use and SSD. The evidence for and against each hypothesis is discussed. Despite new evidence, the exact relationship between cannabis and SSD is unclear. There is no firm evidence that cannabis causes SSD. The evidence for the argument that schizophrenic patients are attracted to cannabis is also not strong. The most plausible explanation is that cannabis use and psychosis proneness may have synergistic effects in a vulnerable minority.

Fewer neurological soft signs among first episode psychosis patients with heavy cannabis use

BACKGROUND

Although neurological soft signs (NSS) have been consistently associated with schizophrenia and a variety of risk factors, few studies have focused on the association between NSS and environmental factors such as cannabis use, particularly in patients with first episode psychosis.

METHODS

We administered the Neurological Evaluation Scale (NES) to 92 patients during their first episode of functional psychosis. Psychopathology was assessed with the Positive And Negative Syndrome Scale (PANSS) and the family history of psychotic disorder was established on the basis of the Family Interview for Genetic Studies (FIGS). We also assessed lifetime cannabis and cocaine use utilizing that specific section of the Composite International Diagnostic Interview. The outcome variable was the presence of high NSS, defined by a score above the median split of the NES score (>21).

RESULTS

Most patients (80/92, 87%) presented a non-affective psychosis. The presence of high NSS showed a significant independent association with not having been a heavy cannabis user (OR=8.3; 95% CI, 2.4-33.3), family history of psychosis (OR=4.3; 95% CI, 1.2-14.9), male sex (OR=4.0; 95% CI, 1.2-14.0), lower score in verbal fluency and higher score in negative symptoms (both p<0.01).

CONCLUSION

Our cross-sectional results support the hypothesis that potentially different pathways associated with the emergence of first episode psychosis may exist, including neurological premorbid alteration and environmental cannabis abuse.

Cannabis and schizophrenia

BACKGROUND

Many people with schizophrenia use cannabis and its effects on the illness are unclear.

OBJECTIVES

To evaluate the effects of cannabis use on people with schizophrenia and schizophrenia-like illnesses.

SEARCH STRATEGY

We searched the Cochrane Schizophrenia Group Trials Register (April 2007) which is based on regular searches of BIOSIS, CENTRAL, CINAHL, EMBASE, MEDLINE and PsycINFO.

SELECTION CRITERIA

We included all randomised trials involving cannabinoids and people with schizophrenia or schizophrenia-like illnesses.

DATA COLLECTION AND ANALYSIS

We extracted data independently. For dichotomous data we calculated relative risks (RR) and their 95% confidence intervals (CI) on an intention-to-treat basis, based on a fixed effects model. We calculated the numbers needed to treat/harm (NNT/NNH). For continuous data, we calculated weighted mean differences (WMD) again based on a fixed effects model.

MAIN RESULTS

We identified one randomised trial. No significant differences were found between the Cannabis and Psychosis Therapy (CAP) intervention group and the Psychoeducaton (PE) intervention for use of cannabis at three months assessment (n=47, RR 1.04 CI 0.6 to 1.7). BPRS-extended scale scores at three months assessment (n=47, WMD -3.60 CI -12.8 to 5.6) and nine months assessment (n=47, WMD 0.80 CI -7.5 to 9.1) were non-significant between CAP and PE. We found no significant improvement in social functioning in the CAP group compared with PE (at 3 months, n=47, WMD -0.80 CI -10 to 8.4) and (at 9 months, n=47, WMD -4.70 CI -14.5 to 5.1).

AUTHORS' CONCLUSIONS

At present, there is insufficient evidence to support or refute the use of cannabis/cannabinoid compounds for people suffering with schizophrenia. This review highlights the need for well designed, conducted and reported clinical trials to address the potential effects of cannabis based compounds for people with schizophrenia.

[Cannabis and psychosis: search of a causal link through a critical and systematic review]

INTRODUCTION

Although cannabis use may be involved in the aetiology of acute psychosis, there has been considerable debate about the association observed between cannabis use and chronic psychosis. In particular, because of the frequent co-occurrence between schizophrenia and cannabis use, the question has been raised of a causal link between exposure to cannabis as a risk factor and the development of psychosis or psychotic symptoms.

OBJECTIVE

The aim of this article was to examine the evidence that cannabis use causes chronic psychotic disorders by using established criteria of causality. These criteria were defined by: biologic plausibility, strength of the interaction between the risk factor and the disease, reprieability of the results, temporal sequence between the exposure to the risk factor and the beginning of the disease and existence of a dose-effect relationship.

METHODS

The selected studies were found in Medline using the keywords "cannabis" and "psychosis", "cannabis" and "schizophrenia", "cannabis" and "psychotic symptoms" and "prospective" or "cohort" or "longitudinal". The selected studies were all prospective studies assessing the temporal sequence between cannabis use and emergence of psychosis or psychotic symptoms. The search strategies resulted in 60 records that were screened by reading both titles and abstracts. Seventeen studies were considered eligible, and then, after reading the full text, seven met the inclusion criteria.

RESULTS

Together, the seven studies were all prospective cohorts and represented 50,275 human subjects. There were three European studies (from Sweden, Holland and Germany), one from New Zealand and one from Australia. Only one study of the seven did not show a significant association between cannabis consumption and increase of the risk of developing a psychosis. However, this study had some bias, such as low level of cannabis use and the lack of evaluation of cannabis use after inclusion. For the six other studies, data show the existence of a significant association between cannabis use and psychotic disorders (with an increased risk between 1.2 and 2.8 in Zammit et al.'s study), particularly among vulnerable individuals (that is with a prepsychotic state at the time of inclusion). Therefore, all the studies that assessed a dose-effect relationship showed this link between cannabis use and the emergence of psychosis or psychotic symptoms. The fact that all causal criteria were present in the studies suggests that cannabis use may be an independent risk factor for the development of psychosis. Results seem to be more consistent for vulnerable individuals with the hypothesis that cannabis use may precipitate psychosis, notably among vulnerable subjects. In particular, early onset of cannabis use during adolescence should be an environmental stressor that interacts with a genetic predisposition to induce a psychotic disorder.

CONCLUSION

The objective of this article was to examine whether cannabis use can be an independent risk factor for chronic psychotic disorders, by using established criteria of causality. Data extracted from the selected studies showed that cannabis use may be an independent risk factor for the development of psychotic disorders. Early screening of the vulnerability to psychotic disorder should permit improved focus on prevention and information about the specific risks related to cannabis use among this population.

Endogenous cannabinoids in patients with schizophrenia and substance use disorder during quetiapine therapy

Disturbances in the endogenous cannabinoid (ECB) system in schizophrenia may contribute to their enhanced sensitivity to psychoactive substances, and the beneficial effects of second-generation antipsychotics for substance abuse in schizophrenia may involve modulatory effects on ECB. To verify these two assumptions, 29 patients (24 completers) with schizophrenia and substance use disorders (SUD) were treated with quetiapine for 12 weeks, and peripheral ECB levels were measured, using high-performance liquid chromatography/mass spectrometry, in patients (weeks 0, 6 and 12) and 17 healthy volunteers. Baseline anandamide levels were significantly higher in patients, relative to controls. This result is consistent with studies describing ECB dysfunctions in schizophrenia. SUD parameters improved during treatment, but no changes in ECB occurred over time. Improvements in substance abuse were probably not mediated by modulatory effects of quetiapine on ECB. Lastly, baseline anandamide predicted endpoint SUD scores (alcohol/ cannabis). Anandamide is a potential target for medications aimed at relieving SUD in schizophrenia.

Cannabis-related psychosis: Presentation and effect of abstinence

BACKGROUND

The correlation between cannabis and negative mental health outcomes has been unequivocally established. Nevertheless, there is still a great need to research different dimensions of cannabis-related disorders, among which the study of cannabis-related psychosis is very important. There is a dearth of research regarding phenomenology and effect of abstinence, particularly from India. This study attempts to research the clinical presentation of cannabis-related psychosis and effect of abstinence.

AIM

The aim of the present study was to document the clinical presentation of cannabis-related psychosis at presentation and after 7 days' abstinence from cannabis.

MATERIALS AND METHODS

Subjects with psychosis following cannabis use without any other prior or concurrent psychiatric disorder presenting to the outpatient department of a large tertiary care hospital were consecutively recruited for study. They were observed in a drug-free, protected environment for 7 days, during which clinical features were recorded using the Brief Psychiatric Rating Scale (BPRS).

RESULTS

Twenty male subjects were recruited and phenomenology was evaluated on the BPRS. Items with highest frequencies were unusual thought content (100%), excitement (75%), grandiosity (75%), hallucinatory behavior (70%) and uncooperativeness (65%). The least common symptoms were anxiety (5%), guilt feeling (5%), depressive mood (10%), motor retardation (10%) and blunted affect (30%). Nine subjects (45%) presented with cognitive dysfunction. Affective psychosis was the predominant diagnosis. At the end of 1 week of abstinence from cannabis, there was a significant decrease in scores. Significant improvement was observed in cognitive dysfunction, conceptual disorganization, grandiosity, tension, hostility, hallucinatory behavior and excitement.

CONCLUSIONS

Cannabis-related psychosis presented with a predominantly affective psychosis and prominent thought disorder, excitement and violence. All subjects showed improvement in symptoms with abstinence from cannabis. A small heterogeneous sample and short duration of observation were the important limitations of this study.

Cannabis use and misuse prevalence among people with psychosis

BACKGROUND

Increasing attention has been given by researchers to cannabis use in individuals with psychosis. As psychoses are relatively low-prevalence disorders, research has been mostly been restricted to small-scale studies of treatment samples. The reported prevalence estimates obtained from these studies vary widely.

AIMS

To provide prevalence estimates based on larger samples and to examine sources of variability in prevalence estimates across studies.

METHOD

Data from 53 studies of treatment samples and 5 epidemiological studies were analysed.

RESULTS

Based on treatment sample data, prevalence estimates were calculated for current use (23.0%), current misuse (11.3%), 12-month use (29.2%), 12-month misuse (18.8%), lifetime use (42.1%) and lifetime misuse (22.5%). Epidemiological studies consistently reported higher cannabis use and misuse prevalence in people with psychosis.

CONCLUSIONS

The factor most consistently associated with increased odds of cannabis prevalence was specificity of diagnosis. Factors such as consumption patterns and study design merit further consideration.

The safety of cannabinoids for the treatment of multiple sclerosis

The evidence for the therapeutic efficacy of cannabinoids in the treatment of multiple sclerosis (MS) is increasing but is not as yet convincing. Although several trials have reported no significant effect, the majority of the evidence which supports a beneficial effect on spasticity and pain is based on subjective measurements in trials where unblinding was likely to be a problem. The available clinical trial data suggest that the adverse side effects associated with using cannabis-based medicinal extracts (CBMEs) are generally mild, such as dry mouth, dizziness, somnolence, nausea and intoxication, and in no case did toxicity develop. However, most of these trials were run over a period of months and it is possible that other adverse side effects, not seen in these short-term studies, could develop with long-term use. Despite the evidence that cannabinoids can disrupt cognitive function and promote depression, on the basis of current data, such adverse effects seem unlikely to be associated with the use of CBMEs. Likewise, there is no evidence to suggest that their effects on balance and motor control, or immune function, may be clinically significant. There is, however, reason to be concerned about the use of therapeutic cannabinoids by people predisposed to psychosis and by pregnant women, given the increasing evidence of their adverse effects on the fetus. In conclusion, given the modest therapeutic effects of cannabinoids demonstrated so far, and the risk of long-term adverse side effects, there is reason to be cautious about their use in the treatment of MS.

Cannabis use and psychotic disorders: an update

This paper evaluates three hypotheses about the relationship between cannabis use and psychosis in the light of recent evidence from prospective epidemiological studies. These are that: (1) cannabis use causes a psychotic disorder that would not have occurred in the absence of cannabis use; (2) that cannabis use may precipitate schizophrenia or exacerbate its symptoms; and (3) that cannabis use may exacerbate the symptoms of psychosis. There is limited support for the first hypothesis. As a consequence of recent prospective studies, there is now stronger support for the second hypothesis. Four recent prospective studies in three countries have found relationships between the frequency with which cannabis had been used and the risk of receiving a diagnosis of schizophrenia or of reporting psychotic symptoms. These relationships are stronger in people with a history of psychotic symptoms and they have persisted after adjustment for potentially confounding variables. The absence of any change in the incidence of schizophrenia during the three decades in which cannabis use in Australia has increased makes it unlikely that cannabis use can produce psychoses that would not have occurred in its absence. It seems more likely that cannabis use can precipitate schizophrenia in vulnerable individuals. There is also reasonable evidence for the third hypothesis that cannabis use exacerbates psychosis.

Cannabis-associated psychosis: current status of research

Cannabis has been used for recreational, medicinal and religious purposes in different cultures since ancient times. There have been various reports of adverse effects due to or associated with cannabis consumption, including psychotic episodes. Historically, our understanding of these clinical observations has been significantly hindered by a lack of knowledge regarding their underlying neurobiological and pharmacological processes. However, the discovery of the endogenous cannabinoid system has allowed a greater understanding of these adverse effects to develop. From a clinical perspective, toxic or transient psychotic reactions to the administration of herbal cannabis preparations or specific cannabinoid compounds have to be differentiated from longer-lasting, persistent schizophrenia-like disorders associated with the use of cannabis/cannabinoids. The latter are most likely to be associated with a predisposition or vulnerability to schizophrenia. Interestingly, the recently suggested role of the endogenous cannabinoid system in schizophrenia not related to previous cannabinoid consumption introduces an additional perspective on the mechanism underlying cannabis-associated schizophrenia-like disorders, as well as on the effects of cannabis consumption in schizophrenia. At present, acute psychopharmacological treatment options for cannabis-associated transient and persistent schizophrenia-like psychotic episodes are similar and are based on the use of benzodiazepines and antipsychotics. However, new pharmacological strategies using the endogenous cannabinoid system as a primary target are under development. Long-term psychotherapeutic treatment options involve case management strategies and are mainly based on specialised psychotherapeutic programmes to encourage cannabis users to stop their use of the drug.

Early adolescent cannabis exposure and positive and negative dimensions of psychosis

AIMS

To investigate the effect of exposure to cannabis early in adolescence on subclinical positive and negative symptoms of psychosis.

DESIGN

Cross-sectional survey in the context of an ongoing cohort study.

SETTING

Government-supported general population cohort study.

PARTICIPANTS

A total of 3500 representative 19-year olds in Greece.

MEASUREMENTS

Subjects filled in the 40-item Community Assessment of Psychic Experiences, measuring subclinical positive (paranoia, hallucinations, grandiosity, first-rank symptoms) and negative psychosis dimensions and depression. Drug use was also reported on.

FINDINGS

Use of cannabis was associated positively with both positive and negative dimensions of psychosis, independent of each other, and of depression. An association between cannabis and depression disappeared after adjustment for the negative psychosis dimensions. First use of cannabis below age 16 years was associated with a much stronger effect than first use after age 15 years, independent of life-time frequency of use. The association between cannabis and psychosis was not influenced by the distress associated with the experiences, indicating that self-medication may be an unlikely explanation for the entire association between cannabis and psychosis.

CONCLUSIONS

These results add credence to the hypothesis that cannabis contributes to the population level of expression of psychosis. In particular, exposure early in adolescence may increase the risk for the subclinical positive and negative dimensions of psychosis, but not for depression.

Adverse effects of cannabis on health: an update of the literature since 1996

Recent research has clarified a number of important questions concerning adverse effects of cannabis on health. A causal role of acute cannabis intoxication in motor vehicle and other accidents has now been shown by the presence of measurable levels of Delta(9)-tetrahydrocannabinol (THC) in the blood of injured drivers in the absence of alcohol or other drugs, by surveys of driving under the influence of cannabis, and by significantly higher accident culpability risk of drivers using cannabis. Chronic inflammatory and precancerous changes in the airways have been demonstrated in cannabis smokers, and the most recent case-control study shows an increased risk of airways cancer that is proportional to the amount of cannabis use. Several different studies indicate that the epidemiological link between cannabis use and schizophrenia probably represents a causal role of cannabis in precipitating the onset or relapse of schizophrenia. A weaker but significant link between cannabis and depression has been found in various cohort studies, but the nature of the link is not yet clear. A large body of evidence now demonstrates that cannabis dependence, both behavioral and physical, does occur in about 7-10% of regular users, and that early onset of use, and especially of weekly or daily use, is a strong predictor of future dependence. Cognitive impairments of various types are readily demonstrable during acute cannabis intoxication, but there is no suitable evidence yet available to permit a decision as to whether long-lasting or permanent functional losses can result from chronic heavy use in adults. However, a small but growing body of evidence indicates subtle but apparently permanent effects on memory, information processing, and executive functions, in the offspring of women who used cannabis during pregnancy. In total, the evidence indicates that regular heavy use of cannabis carries significant risks for the individual user and for the health care system.

The relationship between cannabis use and schizotypal symptoms

To test the relationship between schizotypal symptoms and cannabis use in a non-clinical population, cannabis users and non-users were asked to complete the Schizotypal Personality Questionnaire. Significant differences in scores between the groups were observed. There may be a developmental process in the relationship between cannabis use and schizotypal symptoms.