Sustained and "sleeper" effects of group metacognitive training for schizophrenia: a randomized clinical trial

Cognitive interventions increasingly complement psychopharmacological treatment to enhance symptomatic and functional outcome in schizophrenia. Metacognitive training (MCT) is targeted at cognitive biases involved in the pathogenesis of delusions.

To examine the long-term efficacy of group MCT for schizophrenia in order to explore whether previously established effects were sustained.

A 2-center, randomized, controlled, assessor-blind, parallel group trial was conducted. A total of 150 inpatients or outpatients with DSM-IV diagnoses of schizophrenia spectrum disorders were enrolled. All patients were prescribed antipsychotic medication. The second follow-up assessment took place 3 years later after the intervention phase was terminated.

Group MCT targeting cognitive biases vs neuropsychological training (COGPACK). Patients received a maximum of 16 sessions.

The primary outcome measure was a delusion score derived from the Positive and Negative Syndrome Scale (PANSS). The PANSS positive syndrome and total scores, the Psychotic Symptom Rating Scales, the jumping to conclusions bias, self-esteem, and quality of life served as secondary outcome measures.

The intention-to-treat analyses demonstrated that patients in the MCT group had significantly greater reductions in the core PANSS delusion score, after 3 years compared with the control group (η2partial = .037; P = .05). Among the secondary outcomes, the intention-to-treat analyses also demonstrated that patients in the MCT group had significantly greater reductions in the PANSS positive syndrome score (η2partial = .055; P = .02) and the Psychotic Symptom Rating Scales delusion score (η2partial = .109; P = .001). Significant group differences at the 3-year follow-up were also found on measures of self-esteem and quality of life, which did not distinguish groups at earlier assessment points. Attention was improved in the neuropsychological training group relative to the MCT group. The completion rate was 61.3% after 3 years.

Metacognitive training demonstrated sustained effects in the reduction of delusions, which were over and above the effects of antipsychotic medication. Moreover, there were some unanticipated ("sleeper") effects as both self-esteem and quality of life were improved after 3 years. Effects on self-esteem and well-being were found even in the absence of an improvement on the jumping to conclusions bias.

isrctn.org Identifier: ISRCTN95205723.