Substance use quadrupled the risk of self-harm in schizophrenia patients, with cannabis most commonly involved | Research

The takeaway

Among 165 schizophrenia patients in remission, substance use disorder was associated with a 4-fold increase in non-suicidal self-injury risk, with cannabis and synthetic cannabinoids being the most commonly abused substances in the self-injury group.

Psychiatrists treating schizophrenia, crisis intervention specialists, and substance use researchers.

4-fold increase in self-harm risk with substance use disorder

What the researchers found

Substance use disorder increased NSSI risk approximately 4-fold. The NSSI prevalence was 43.6%, with self-cutting as the most common method and affect regulation as the primary motivation. Cannabis and synthetic cannabinoids were the most commonly abused substances among patients with NSSI.

Why it matters

The finding that substance use, particularly cannabis and synthetic cannabinoids, is a modifiable risk factor for self-harm in schizophrenia patients has direct clinical implications for prevention and treatment.

The numbers in context

165 patients. NSSI prevalence: 43.6%. Lifetime SUD rate: 38.2% overall, 55.6% in NSSI group. SUD associated with ~4-fold increase in NSSI risk. Most common substances in NSSI group: cannabis and synthetic cannabinoids.

How the study worked

Cross-sectional study of 165 patients with schizophrenia spectrum disorders in remission. NSSI was assessed using the Inventory of Statements About Self-injury (ISAS). Lifetime substance use disorders were evaluated. Logistic regression identified predictors.

What this study cannot tell us

Cross-sectional design cannot establish causation. The sample was limited to patients in remission, which may not represent those with active psychosis. The role of specific substances (cannabis vs. synthetic cannabinoids) was not disaggregated.

How to read the evidence

Moderate: adequate sample with validated instruments, though cross-sectional and limited to patients in remission.

When this study was published

Published in 2020 in Asian Journal of Psychiatry.

The bigger picture

Non-suicidal self-injury is a significant predictor of future suicide attempts. Identifying and treating substance use in schizophrenia patients could reduce both NSSI and downstream suicide risk.

Questions still open

Would substance use treatment reduce NSSI rates in schizophrenia patients? Do synthetic cannabinoids pose a greater self-harm risk than natural cannabis? Is the cannabis-NSSI link specific to schizophrenia or present in other psychiatric populations?

Common questions

Why do schizophrenia patients self-harm?

The most common reason reported was affect regulation, meaning patients used self-injury to manage overwhelming emotions. Previous suicide attempts were also a significant predictor of NSSI.

What was the role of cannabis specifically?

Cannabis and synthetic cannabinoids were the most commonly abused substances among schizophrenia patients who self-injured. Substance use disorder overall was associated with a 4-fold increase in self-injury risk.

Read the original research

Predicting factors for non-suicidal self-injury in patients with schizophrenia spectrum disorders and the role of substance use.

Asian journal of psychiatry, 52, 102068

View on PubMed ↗Publisher’s paper ↗

Citation

Güney, Erengül; Alnıak, İzgi; Erkıran, Murat. (2020). Predicting factors for non-suicidal self-injury in patients with schizophrenia spectrum disorders and the role of substance use.. Asian journal of psychiatry, 52, 102068. https://doi.org/10.1016/j.ajp.2020.102068