Rasmussen SA, et al. - This observational study was performed to determine whether the predictive value of early antipsychotic response persisted throughout long-term treatment over multiple years. The outcomes revealed the long-term prognostic value of early haloperidol response. The predictive value of early olanzapine response could be less robust.

• The authors performed follow-up assessments of 64 patients with first-episode psychosis an average of 25 months after they began antipsychotic treatment.
• They initially randomized patients to receive haloperidol or olanzapine, but treatment after the acute hospitalization period was not controlled.
• They used regression analyses to determine whether early improvement on the Brief Psychiatric Rating Scale at 2 or 3 weeks predicted longer term improvement at follow-up.
• To determine whether early response could predict extrapyramidal side effects at follow-up, they conducted secondary analyses.

• At 2 weeks, early response to haloperidol predicted Brief Psychiatric Rating Scale improvement on longer-term follow-up (p = .002).
• Longer term improvement was not foretold by early response to olanzapine at 2 weeks (p = .726) or 3 weeks (p = .541).
• Between treatment groups, rates of extrapyramidal side effects did not differ and were not predicted by early response.