Relapse may contribute to antipsychotic treatment resistance

Relapse following effective treatment of the first episode of schizophrenia may reduce or delay antipsychotic treatment response, a recent study has shown.

Patients with a diagnosis of first-episode schizophrenia or schizoaffective disorder who met the following criteria were included: referral to the First-Episode Psychosis Program between 2003 and 2013; treatment with an oral second-generation antipsychotic according to a standardized treatment algorithm; positive symptom remission; subsequent relapse (ie, second episode) in association with nonadherence; and reintroduction of antipsychotic treatment with the same agent used to achieve response in the first episode.

Outcomes used as an index of antipsychotic treatment response were as follows: changes in the brief psychiatric rating scale total and positive symptom scores and number of patients who achieved positive symptom remission and 20- and 50-percent response.

One hundred thirty patients were analysed, and all of them took the same antipsychotic drug in both episodes. However, significant episode-by-time interactions occurred for all outcomes of antipsychotic treatment response over 1 year in favour of the first vs the second episode (50-percent response rate: 48.7 percent vs 10.4 percent at week 7; 88.2 percent vs 27.8 percent at week 27, respectively).

There were significantly higher antipsychotic doses in the second vs the first episode, but the results remained unchanged after adjusting for antipsychotic dose.

“Although some studies have suggested that relapse may be associated with antipsychotic treatment resistance in schizophrenia, the number and quality of studies is limited,” the investigators noted.