Neural correlates of Cognitive Behavioural Therapy effects on positive symptoms in patients with schizophrenic disorders

The topic neural correlates of Cognitive Behavioural Therapy (CBT) effects in treatment of psychotic disorders has only been investigated for very small sample sizes. Thus the multicentre fMRI study evaluated a large sample of psychotic patients (n = 98) and controls (n = 89) from the POSITIVE clinical trial for the neural correlates of normal and pathological cognitive processes implicated in delusional thought, the potential modulations of components of the neural circuit by CBT and its differences to effects of Supportive Therapy (ST).‏ Patients were examined and re-examined before and after nine months of therapy (either with CBT or ST). Differences in brain activation relating to phenomena of premature reasoning (JTC-task) and biased attribution (AB-task) were analyzed. The fMRI measurements before psychotherapy showed activations in key areas for decision making for the JTC-task and evaluative processes for the AB-task. The comparison of patients with schizophrenia and healthy controls revealed significant decreased activations in these regions in patients. After nine months of psychotherapy the preliminary data analysis of the still blinded treatment arms showed significantly increased activations in the mentioned brain areas. These findings suggest neuroplastic changes due to relearning strategies in patients with chronified psychosis. This is an encouraging result, hopefully leading to a more widespread application of psychotherapy in treatment of schizophrenia.