Cannabis use in first episode psychosis: what we have tried and why it hasn't worked

Comparing the medication costs of treating patients with schizophrenia who use cannabis with those who do not

Background

Cannabis use is more prevalent among people with schizophrenia than in the general population. This usage detrimentally impacts disease prognosis, contributing to escalated admissions, heightened severity of psychotic symptoms, and reduced medication response. The recent decriminalisation of cannabis in South Africa may lead to an upsurge in usage, consequently intensifying the strain on mental healthcare services.

Aim

This study aimed to compare the medication costs of patients with schizophrenia depending on cannabis use.

Setting

Weskoppies Hospital, Pretoria, South Africa, 2018-2019.

Methods

Data pertaining to medication expenses during the 2018-2019 period were acquired from the hospital pharmacy. Data were collected from 114 patient records to form two equal cohorts: one exposed to cannabis and the other non-exposed, as indicated by urine drug screens or admission of cannabis use. Medications prescribed from admission to time of being ready for discharge were recorded and corresponding costs were calculated.

Results

Patients who were exposed to cannabis had higher medication costs (R 516.47) than patients who were non-exposed (R 328.69) (p = 0.0519), over the whole admission period.

Conclusion

Cannabis exposure escalates the financial burden of treating schizophrenia at Weskoppies Hospital. This might be attributed to failure of cost-effective, first-line medications prompting the prescription of costlier, second-line alternatives or higher prescribed dosages.

Contribution

This study contributes to findings that it is more expensive to treat patients with schizophrenia who have relapsed, if they are using cannabis. This finding has future cost implications when budgeting for pharmacotherapeutic treatment.

Exploration of cannabis use and polygenic risk scores on the psychotic symptom progression of a FEP cohort

Cannabis use is highly prevalent in first-episode psychosis (FEP) and plays a critical role in its onset and prognosis, but the genetic underpinnings promoting both conditions are poorly understood. Current treatment strategies for cannabis cessation in FEP are clearly inefficacious. Here, we aimed to characterize the association between cannabis-related polygenic risk scores (PRS) on cannabis use and clinical course after a FEP. A cohort of 249 FEP individuals were evaluated during 12 months. Symptom severity was measured with the Positive and Negative Severity Scale and cannabis use with the EuropASI scale. Individual PRS for lifetime cannabis initiation (PRS_CI) and cannabis use disorder (PRS_CUD) were constructed. Current cannabis use was associated with increased positive symptoms. Cannabis initiation at younger ages conditioned the 12-month symptom progression. FEP patients with higher cannabis PRS_CUD reported increased baseline cannabis use. PRS_CI was associated with the course of negative and general symptomatology over follow-up. Cannabis use and symptom progression after a FEP were modulated by cannabis PRS, suggesting that lifetime initiation and use disorders may have partially independent genetic factors. These exploratory results may be the first step to identify those FEP patients more vulnerable to cannabis use and worse outcomes to ultimately develop tailored treatments.

Barriers and Facilitators That Influence Providers' Ability to Educate, Monitor, and Treat Substance Use in First-Episode Psychosis Programs Using the Theoretical Domains Framework

In this qualitative study, we explore providers' experiences with addressing substance use among individuals with first-episode psychosis (FEP) enrolled in coordinated specialty care (CSC) programs. Three focus groups were conducted with 24 providers from CSC programs for FEP in Washington. Questions were focused on barriers and facilitators to addressing substance use using the Theoretical Domains Framework (TDF) as a guide. Thematic analysis was used to code all transcripts. Identified TDF domains were then mapped onto the COM-B (Capability, Opportunity, Motivation, Behavior) intervention functions and behavior change techniques. Seven theoretical domains were identified as the most relevant to addressing substance use: "Knowledge," "Skills," "Environmental Context and Resources," "Social Influences," "Social and Professional Role and Identity," "Beliefs about Capabilities," and "Reinforcement." The use of the TDF provides a framework to explore barriers and facilitators for targeting substance use and suggestions for behavior change techniques when considering implementation of evidence-based strategies to enhance CSC models.