Discontinuing cannabis use: Symptomatic and functional outcomes in people with an established psychotic disorder.

For people with psychotic disorders, the negative outcomes associated with continuing cannabis use would suggest that discontinuing such use may be beneficial for their symptomatic and functional recovery. However, existing evidence that discontinuation is associated with better clinical outcomes is inconsistent and it remains unclear whether discontinuing use is associated with improvements in outcomes for people with an established psychotic disorder. In this 3-5-year longitudinal study we examined baseline and follow-up symptomatic and functional profiles of 371 people with an established psychotic disorder, comparing those who continued to use cannabis with those who discontinued use after baseline assessment. At follow-up, one third (33.3 %) of baseline cannabis users had discontinued use. Discontinuation was associated with significantly lower odds of past-year hallucinations and a mean improvement in level of functioning (Personal and Social Performance Scale) compared to a decline in functioning in continuing users. No significant differences in severity of negative symptoms were observed. With few longitudinal studies examining symptomatic and functional outcomes for people with established psychotic disorders who continue to use cannabis compared to those who discontinue use, our findings that discontinuing cannabis was associated with significant clinical improvements fill gaps in the evidence-base.

Is cannabis a risk factor for suicide attempts in men and women with psychotic illness?

OBJECTIVE: To investigate whether recent cannabis use by men and women with psychotic disorders was associated with increased risk of suicide attempt, and to determine associated factors, stratified by sex. METHODS: Data from 1065 men and 725 women interviewed in the Australian national survey of psychosis were analysed to model separately, for each sex, the impact of daily, casual or no past-year cannabis use and other risk factors including age, on a past-year suicide attempt. RESULTS: In the past year, 168 (9.4%) participants attempted suicide. Unadjusted analyses showed daily cannabis users of both sexes had significantly increased odds of attempting suicide compared to non-users. After adjusting for confounding factors, this relationship was no longer significant. Depression had the strongest association with attempting suicide for both sexes. Sex differences in other risk factors were observed. In post hoc analysis, daily cannabis use was associated with higher odds of attempting suicide in older men compared to non-users; this was not found in younger men or women. CONCLUSIONS: Associations between past-year cannabis use and suicide attempts were confounded by other factors (depression, loneliness, homelessness and hallucinations). The possibility of greater risk of suicidal behaviour with regular cannabis use for older men should be considered.

Metabolic syndrome in people with a psychotic illness: is cannabis protective?

BACKGROUND: Rates of the metabolic syndrome in people with psychotic illness are high. Emerging evidence suggests that cannabis use may have a positive impact on cardiometabolic risk factors in the general population, but little is known about its impact for people with psychotic illness. Our aim was to investigate whether the rate of the metabolic syndrome in people with psychotic illness was associated with frequency of cannabis use. METHOD: The 2010 Australian psychosis survey used a two-phase design to randomly select a nationally representative sample of 1825 adults with psychotic illness for interview and physical assessment. This study is based on 1813 participants who provided data on cannabis use. Multiple logistic regression was used to model the influence of frequency of cannabis use on the metabolic syndrome, adjusting for potential covariates including antipsychotic medication use, smoking, alcohol use and cognitive function. RESULTS: One-third (33.0%) of participants had used cannabis in the past year. The proportion of non-users, occasional users and frequent users with the metabolic syndrome was 63.0, 51.7 and 43.5%, respectively (p < 0.001). In unadjusted analyses, both occasional use and frequent cannabis use were associated with significantly lower odds of the metabolic syndrome. In the adjusted analyses, the association between the metabolic syndrome and frequent cannabis use remained significant [odds ratio = 0.56, 95% confidence interval (CI) 0.39-0.80], but not the association with occasional use (odds ratio = 0.75, 95% CI 0.49-1.13). CONCLUSIONS: While cannabis use may be detrimental for mental health, these data suggest that it may also have a cardiometabolic protective effect. Further investigation is required to understand the mechanism underlying this paradoxical finding.