Dose-Response Relationship Observed Between CBT, Reduction in Schizophrenia Symptoms

A dose-response relationship between cognitive behavioral therapy (CBT) and improvement in schizophrenia symptoms was suggested by research findings published in Schizophrenia Research.

Researchers performed a secondary analysis of the Assessment of Cognitive Therapy Instead of Neuroleptics (ACTION) trial, which investigated the effect of CBT in patients with schizophrenia who were not taking antipsychotic medication. Patients were randomly assigned to receive either CBT in addition to treatment as usual (n=37) or treatment as usual (n=37) for 9 months. Investigators assessed change in the Positive and Negative Symptoms Scale (PANSS) as primary outcome measure.

Instrument variable methods demonstrated that each CBT session reduced PANSS total score by approximately 0.6 points (P =.031). Therefore, length of treatment exposure was identified as a significant variable in predicting symptom improvement. Per analyses stratified by treatment mode, patients who received a longitudinal formulation in the first 4 CBT sessions had poorer treatment outcomes compared with patients who received a maintenance formulation, although the results were not statistically significant (P =.173). Other CBT components, including homework, cognitive techniques, and behavioral strategies, were not indicated as predictive of a significantly improved treatment response.

Researchers concluded that the dose-response relationship observed between CBT and schizophrenia outcome may be salient to clinicians in titrating treatment strategies. However, the study was limited by its small sample size and the assumption that CBT affected PANSS scores linearly across sessions. Additional investigation is necessary to further clarify the relationship between CBT exposure and symptom improvement in patients with schizophrenia.

Disclosures: Douglas Turkington, Anthony P. Morrison, Alison Brabban, Paul Hutton and Robert Dudley are practitioners of CBTp and deliver this intervention within the UK National Health Service. Douglas Turkington, Anthony P. Morrison, Alison Brabban and Robert Dudley receive royalties from texts or books they have published on CBTp. Helen M. Spencer, Douglas Turkington, Anthony P. Morrison, Alison Brabban and Robert Dudley have received lecturing fees for delivering CBTp workshops across the UK and internationally. All other authors declare that they have no conflicts of interest.

Reference

Spencer HM, McMenamin M, Emsley R, et al. Cognitive behavioral therapy for antipsychotic-free schizophrenia spectrum disorders: Does therapy dose influence outcome? [published online July 11, 2018] Schizophr Res. doi:10.1016/j.schres.2018.07.016