Medication adherence in first episode psychosis: the role of pre-onset subthreshold symptoms

The experience of pre-onset subthreshold psychotic symptoms (STPS, signifying a clinical high-risk state) in first episode psychosis (FEP) predicts poorer outcomes during treatment, possibly through differential adherence to medication. We explored whether adherence differs between FEP patients with and without pre-onset STPS.

Antipsychotic medication adherence was compared in 263 STPS+ and 158 STPS- subjects in a specialized early intervention program for FEP. Data were gathered from a larger observational study conducted between 2003 and 2016. STPS status, sociodemographic, and baseline clinical variables were tested as predictors of non-adherence using univariate and multivariate logistic regressions. Time to onset of non-adherence was analyzed using Kaplan-Meier curves. The same predictors were tested as predictors of time to onset of non-adherence using Cox regression models.

Medication non-adherence was higher in STPS+ participants (78.9% vs. 68.9%). STPS status (OR 1.709), substance use disorder (OR 1.767), and milder positive symptoms (OR 0.972) were significant baseline predictors of non-adherence. Substance use disorder (HR 1.410), milder positive symptoms (HR 0.990), and lack of contact between the clinical team and relatives (HR 1.356) were significant baseline predictors of time to non-adherence.

FEP patients who experience pre-onset STPS are more likely to be non-adherent to antipsychotic medication over 2 years of intervention. FEP programs should routinely evaluate pre-onset symptomatology to deliver more personalized treatments, with emphasis on engaging both patients and family members from the beginning of care.