Substance-Induced Psychosis and First-Episode Psychotic Disorders: Premorbid Risks, Labour Market Outcomes, and Antipsychotic Use
J. Jeyapalan, S. Niemela, H. TaipaleIntroduction
Substance-induced psychosis (SIP) is often considered a transient condition, yet growing evidence suggests its burden may resemble that of first-episode psychotic disorders (FEPD). Comparative data on premorbid risks, labour market outcomes, and pharmacological treatment remain scarce.
Objectives
To compare sociodemographic, psychiatric, and work-related characteristics between SIP and FEPD. To evaluate prevalence and patterns of antipsychotic use before and after the first psychotic episode. To assess subtype-specific treatment trends and medications prescribed among SIP patients.
Methods
Nationwide Swedish health registers (2006–2016) identified 7,320 SIP cases (ICD-10 F1X.5, excluding tobacco) and matched them 1:1 with FEPD (F20–F29) by age, sex, and calendar year. Premorbid psychiatric morbidity, self-harm, employment, sickness absence, and disability pension were examined. Antipsychotic use was analysed from three years before until three years after diagnosis, stratified by SIP subtype (alcohol, cannabis, amphetamine, multi-use). Prescriptions were classified by active substance using the ATC system.
Results
SIP patients showed higher rates of ADHD (14.4% vs 8.9%), substance use disorder (68.3% vs 22.3%), and self-harm (22.9% vs 11.3%) compared with FEPD, but lower rates of depression, anxiety, autism, and intellectual disability. They were more often unemployed (24.6% vs 18.6%) and less frequently on sickness absence (8.6% vs 9.9%) or disability pension (18.6% vs 26.3%).
Antipsychotic use peaked 6 months post-diagnosis (23% SIP vs 54% FEPD) and stabilised at 3 years (20% vs 50%). First-year cumulative prevalence: 43% SIP vs 73% FEPD. Cannabis-SIP had the highest prevalence (64.6%), followed by multi-use (50.1%), amphetamine (38.4%), and alcohol (25.2%).
Medication patterns revealed olanzapine as the most prescribed (35% overall; 44% in cannabis-SIP), quetiapine more common in amphetamine-SIP (10%), and risperidone more frequent in FEPD (10% vs 6% in SIP). Use of multiple antipsychotics was higher in FEPD (41.8%) compared to SIP (34.9%).