156. Continued Cannabis and Substance Use in the First 2 Years Following Onset of Psychosis: Predicting Risk of Medication Nonadherence

摘要

>Background: Medication adherence during the early period following first episode of psychosis (FEP) is a key factor that determines outcome and subsequent course of the illness. Uncertainty exists whether the use of nonprescription psychoactive substances following onset, in particular cannabis use, affects medication adherence. >Methods: Two hundred and thirty three FEP patients presenting to psychiatric services in South London were included. Data obtained through prospective assessments (face-to-face and clinical notes) measured medication adherence, pattern of cannabis use (combining measures of continuation of cannabis use with type of cannabis used), and pattern of other substance use (cigarettes, alcohol, and illicit drugs) in the first 2 years following onset of psychosis. Simple and multiple logistic regression analyses were employed to compare the different substance use groups with regard to risk of medication nonadherence while controlling for confounders. >Results: The proportion of nonadherent patients was higher in those who continued using high-potency forms of cannabis (skunk-like) following the onset (83%) when compared to never regular users (51%). This effect remained significant ([Odds Ratio (OR) 5.26, 95% Confidence Interval (CI) 1.91–15.68]) in multiple analysis. No significant increases in risk were present in those who used cannabis more sporadically ([OR 2.03, 95% CI 0.76–5.68]) or used milder forms of cannabis (hash-like) ([OR 1.50, 95% CI 0.28–9.22]). Other substances did not make an independent contribution in this model, including cigarette use ([OR 0.88, 95% CI 0.41–1.89]), alcohol use ([OR 0.66, 95% CI 0.27–1.64]), or regular use of other illicit drugs ([OR 1.03, 95% CI 0.34–3.15]) following the onset. >Conclusion: Continued use of high-potency forms of cannabis following the onset of psychosis is likely to adversely affect medication adherence. Interventions aimed at improving medication adherence should focus on comorbid cannabis use as a preventable risk factor and need to be implemented early in the course of psychosis.