Short-term antipsychotic treatment response in early-onset, typical-onset, and late-onset first episode schizophrenia

In schizophrenia, the age at illness onset may reflect genetic loading and predict prognosis. We aimed to compare the pre-treatment symptom profiles and clinical symptom responses to antipsychotic treatment of individuals with late-onset schizophrenia (LOS; onset age: 40-59 years) with individuals with early-onset schizophrenia (EOS; onset age < 18 years) or typical-onset schizophrenia (TOS; onset age: 18-39 years). We conducted an 8-week cohort study in inpatient departments of five mental health hospitals in five cities in China. We included 106 individuals with LOS, 80 with EOS, and 214 with TOS. Their onset of schizophrenia was within three years and the disorders were minimally treated. The Positive and Negative Syndrome Scale (PANSS) was used to evaluate clinical symptoms at baseline and after 8 weeks of antipsychotic treatment. Mixed effect models were used to compare symptom improvement within eight weeks. Antipsychotic therapy reduced all PANSS factor scores in all three groups. LOS had significantly better improvement in PANSS positive factor scores than EOS at week 8 after adjusting for sex, duration of illness, dose equivalents of antipsychotics at baseline, sites as fixed effects, and individuals as random effects. LOS was associated with reduced positive factor scores at week 8 when receiving 1 mg olanzapine dose equivalent per 1 kg body weight compared with EOS or TOS. In conclusion, LOS had better early improvement of positive symptoms than EOS and TOS. Thus, personalized treatment for schizophrenia should consider the age of onset.