Background: The extent of heterogeneity in antipsychotic treatment response for over extended period is unclear. This study aimed to quantify treatment response trajectories and their characteristics up to 2 years in recent-onset psychosis.
Method: Participants were from a double-blind randomized controlled trial of recent-episode psychosis (N = 263). Recurrent Positive and Negative Syndrome Scale (PANSS) administrations were used to index treatment response trajectories for up to 2 years. Trajectories were calculated with mixed-mode latent class regression modeling from which groups were derived. Group differences were examined on sex, age of first admission, duration of untreated psychosis, premorbid functioning, diagnoses of substance abuse and schizophrenia, and cognitive functioning.
Results: Five trajectories based on PANSS total scores were identified at 2 years. In the trajectory group (23.1%) with the most improvement, approximately 62% met the PANSS 30% change criteria. Logistic regression modeling indicated that membership in the trajectory with the most improvement was significantly (P < 0.05) predicted by absence of a diagnosis of schizophrenia, better premorbid functioning, and higher cognitive scores. Membership in the trajectory with the least improvement was significantly predicted by higher PANSS baseline scores.
Conclusions: Based on clinical trial data, treatment response in early episode psychosis seems to be characterized by amelioration and ongoing change. Premorbid functioning, cognitive functioning, and early symptom severity have prognostic value in predicting treatment response trajectories. Across trajectory studies, approximately 16% of patients experience a dramatic treatment response trajectory characterized by approximately a 60% to 80% symptom reduction.