The SWITCH study: rationale and design of the trial.

Many patients do not respond to the first antipsychotic drug prescribed, but require multiple trials with different drugs before response is achieved. Current treatment guidelines vary substantially in their recommendations as to how long clinicians should wait before an antipsychotic treatment attempt should be considered as failed and the compound switched. It has, however, recently been shown that poor early response to an antipsychotic is associated with continuous poor later response in the course of the same treatment attempt. This finding suggests that patients who do experience poor early response might benefit from a switch in antipsychotic medication as early as 2 weeks after treatment initiation. In the SWITCH trial, 350 patients suffering from an acute episode of schizophrenia are randomly assigned to double-blind treatment with either olanzapine or amisulpride. The primary endpoint is symptomatic remission at week 8. Patients not experiencing at least minor response after 2 weeks are randomized again to either staying on the initially assigned drug or being switched to the alternative compound for another 6 weeks. In case early switching proves superior to maintaining treatment, time wasted for unsuccessful treatment attempts could be minimized, patients' outcomes improved, duration of hospital stays reduced, and thus overall treatment expenses saved. The current report will present the methods of the trial, focusing on various specific features which could be adopted by future studies.