Background and objectives: The treatment of negative symptoms in schizophrenia is a major challenge for mental health care. One randomized controlled trial found that cognitive therapy for low-functioning patients reduced avolition and improved functioning, using an average of 50.5 treatment sessions over the course of 18 months. The aim of our current pilot study was to evaluate whether 20 sessions of Cognitive Behavioral Therapy for negative symptoms (CBT-n) would reduce negative symptoms within 6 months. Also, we wanted to test the cognitive model of negative symptoms by analyzing whether a reduction in dysfunctional beliefs mediated the effects on negative symptoms.
Method: In an open trial 21 adult outpatients with a schizophrenia spectrum disorder with negative symptoms received an average of 17.5 sessions of CBT-n. At baseline and end-of-treatment, we assessed negative symptoms (PANSS) and dysfunctional beliefs about cognitive abilities, performance, emotional experience, and social exclusion. Bootstrap analysis tested mediation.
Results: The dropout rate was 14% (three participants). Intention-to-treat analyses showed a within group effect size of 1.26 on negative symptoms (t = 6.16, | Sig = 0.000). Bootstrap analysis showed that dysfunctional beliefs partially mediated the change.
Limitations: The uncontrolled design induced efficacy biases. Also, the sample was relatively small, and there were no follow-up assessments.
Conclusions: CBT-n may be effective in reducing negative symptoms. Also, patients reported fewer dysfunctional beliefs about their cognitive abilities, performance, emotional experience, and social exclusion, and this reduction partially mediated the change in negative symptoms. The reductions were clinically important. However, larger and controlled trials are needed.
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