Are patients who present to the ED with substance use and psychosis at higher risk of developing schizophrenia?

Question

Are patients who present to the ED with substance use and psychosis at higher risk of developing schizophrenia?

The Study

In September 2023, JAMA Psychiatry published a study to answer this question. Specifically, the authors wanted to determine:

1. Relative and absolute risk of schizophrenia spectrum disorder (schizophrenia or schizoaffective disorder) after initial ED visit for substance use with or without psychosis.
2. Risk by substance type, age, and sex.

The Measure:

The study was a retrospective review of the provincial health system data for all ED visits in Ontario, Canada between January 2008 and March 2022.

Inclusion Criteria

• Age 14-65
• ED visit for substance use with and without psychosis

Exclusion Criteria

• Patient with prior hospitalizations, ED visits, or outpatient visits for psychosis in the previous 2 years.

The population:

• 9,844,497 patients were identified
• 407,737 patients had an initial visit for substance abuse
• 13,784 patients experienced substance-induced psychosis

What Did They Find?

• Patients with substance-induced psychosis had 163 times the risk of developing a schizophrenia spectrum disorder. (3-year risk, 18.5% vs 0.1%)
• Patients with substance use but no psychosis had a lower risk of developing schizophrenia spectrum disorder, but still almost 10 times higher than the general population (3-year risk, 1.4% vs 0.1%)
• Cannabis presented the highest hazard ratio in the population with psychosis.
• Amphetamines, polysubstance use, and cannabis presented the highest risk in the population without psychosis.
• The absolute number of cases of schizophrenia spectrum disorder was higher in the population without psychosis than with psychosis (9969 vs 3029). The authors attribute this to the higher number of total ED substance use visits without psychosis.
• The highest risk was among younger males, especially those using cannabis.

Conclusion

The findings of this cohort study suggest that ED visits for substance use were associated with an increased risk of developing a schizophrenia spectrum disorder. Although substance-induced psychoses had a greater relative transition risk, substance use without psychosis was far more prevalent and resulted in a greater absolute number of transitions. Several factors were associated with higher transition risk, with implications for counseling and early intervention.

Limitations

• No detailed data form outpatient visits for substance abuse was present in the database.
• The study type does not allow a conclusion regarding the cause of the schizophrenia spectrum disorder. The strongest conclusion that can be made from a retrospective study is a determination of an association between substance use and schizophrenia spectrum disorders.

Read The Original Article

Myran DT, Harrison LD, Pugliese M, Solmi M, Anderson KK, Fiedorowicz JG, Perlman CM, Webber C, Finkelstein Y, Tanuseputro P. Transition to Schizophrenia Spectrum Disorder Following Emergency Department Visits Due to Substance Use With and Without Psychosis. JAMA Psychiatry. 2023 Nov 1;80(11):1169-1174. doi: 10.1001/jamapsychiatry.2023.3582. PMID: 37755727; PMCID: PMC10535000.