Illness-related outcomes of illicit substance use disorder in adolescents with early onset schizophrenia: a multicenter study.

ABSTRACT

OBJECTIVES: Lifetime co-occurring substance use disorders are common at the time of presentation for the treatment of primary psychosis. Our aim was to investigate the clinical characteristics of adolescents with early-onset schizophrenia/schizoaffective disorder (EOS), categorized as either with (EOS + SUD) or without SUD (non-SUD/EOS), in a multi-center sample. METHODS: Between 2016 and 2022, 255 patients were evaluated across three tertiary-care inpatient units. Diagnoses were confirmed by the treating physician according to the DSM-5 during the hospital stay. The severity of symptoms was measured using the Positive and Negative Syndrome Scale (PANSS). RESULTS: The EOS + SUD group exhibited a higher illness onset, fewer years of education, longer duration of untreated psychosis (DUP), a higher frequency of male gender, more frequent hospitalizations, increased use of clozapine and zuclopenthixol LAI, along with higher rates of post-traumatic stress disorder and conduct disorder. Notably, differences in DUP, clozapine use, and the number of hospitalizations did not persist in the multivariate logistic regression model. CONCLUSIONS: Our findings support the notion of SUD playing a role in modifying the course of illness in EOS. Future studies should emphasize exploring treatment responses to medications and interventions among youth with dual diagnoses.