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Background: Schizophrenia ranks among the severe psychiatric disorders with a high degree of psychological strain, and delusions are present in more than 65 % of patients. New epidemiological studies proved delusional beliefs to be present in the general population as well which points to a continuum between normal and psychotic experiences. This knowledge paved the way to apply an efficacy of Cognitive Behaviour Therapy and a new form of Cognitive Behaviour Therapy for psychosis (CBT-p) arose. Plentiful randomized controlled trials demonstrated that CBT-p reduces positive symptoms, negative symptoms and depression and enhances social functioning. Even though research in this field is abundant the effect on delusion remains unclear. Therefore, the question arises how therapy can be improved with the objective to reduce delusions. One option results from the `causal interventional approach` that claims a focus on change of potential mediating factors of delusion and not on the symptoms itself. Scientific research shows a stable correlation of emotional factors such as negative self-perception; negative emotions as depression, anxiety and worrying; emotion regulation and insomnia with delusional beliefs. In addition, interventions focussing on a change in these factors were successful.
Altogether, approaches to possible causal factors of delusion in particular emotional factors and refraining from challenging delusional beliefs directly seem to be worthwhile aims. Against this background, Mehl (2013) developed a new form of CBT-p by combining already investigated interventions and adapting them to basic research concerning the formation of delusion. Emotion-oriented Cognitive Behaviour Therapy (CBT-E) was created as a comprehensive form of treatment that indirectly draws on delusional beliefs by improving emotion regulation, reducing negative emotions, increasing self-esteem and sleep-quality. The efficacy of CBT has proven to be significantly improved by homework. In this way, newly learned cognitive methods can be trained and emotional regulation skills can be practiced in daily life. In depression- therapy, cotherapists who support patients in their daily life and with their homework assignments have proven successful. Furthermore, interventions performed by non- professional cotherapists showed a comparable effect in reducing depression to interventions performed by trained therapists. Therefore, it can be assumed, that additional sessions with a cotherapist enhance the implementation of new skills and homework and improve the efficacy of CBT-interventions.
The purpose of this study was to firstly appraise the efficacy of the newly developed CBT-E in a Pre-Post-design. Symptoms of delusion, positive symptoms, negative symptoms, symptoms of schizophrenia in general, depression, functioning and satisfaction with life were tested. A further Pre-Post-analysis evaluated whether it comes to a modification of causal factors (mediators) such as negative emotions, low self- esteem or negative evaluations of self and others, unfavourable emotion regulation techniques and insomnia. Multiple linear regression analyses were used to test a possible enhancement of therapy-efficacy as a result of additional cotherapists. A single- blinded randomized controlled pilot study was performed that compared CBT-E with standard care and enrolled 64 patients. Symptoms mentioned above were assessed at start of therapy, post therapy and after a follow-up period of one year. All patients were offered an additional training with a cotherapist in the form of a student with a Bachelor degree of Psychology.
Results: Pre-Post-analysis of the primary and secondary outcomes revealed a reduction of delusional symptoms, positive, negative, general symptoms as well as an enhancement of social functioning and satisfaction with life. Effect sizes of post- treatment measures were mainly moderate (when rated by therapists or blinded raters) and small (when rated by patients themselves using questionnaires). Only the effects on social functioning did not show a stable improvement. After one year, results across all outcome measures were more distinct, with partially large effect sizes. There were only a few measures of potential emotional factors that have been enhanced after therapy. Depression, rumination and worrying were slightly reduced after therapy and emotion regulation techniques were slightly enhanced. Furthermore, negative self-evaluations decreased and positive self-evaluations increased. Sleeping habits, self-compassion and evaluations of others were not influenced by therapy. Patients who agreed to meet with an additional cotherapist were benefitting less from therapy with respect to measures of delusion and general psychopathology. Other measures did not show significant alteration as a result of additional cotherapist sessions.
Conclusion: Compared to other published studies that tested Cognitive Behavioural Therapies for patients suffering from schizophrenia spectrum disorders, CBT-E did not show a clear superiority. For this reason and in order to arrive at a final conclusion, further statistical analyses of the randomised controlled trial are needed to compare therapy with treatment as usual. In addition, further more rigorously planned multi-centric randomized-controlled trials are necessary and the present study provides a first estimate in order to plan a sufficient sample size for a future study. If this study is successful, a new form of therapy that is less stressful for the therapeutic alliance and easy to learn could be implemented. Improvements concerning potential emotional factors in the formation of delusion were not as stable and clear as improvements in other studies that only focus on one of the tested factors. Nonetheless, reduction of negative emotions, improvement of functional emotion regulation and less negative self-evaluations were found. Therefore, the intervention could be used for emotional stabilization or patients with strong negative self-evaluations. To draw definitive conclusions regarding the effectiveness of the therapy as a result of modifications of emotional factors, mediation analyses should be undertaken. Potential reasons for the disadvantage of cotherapists are the cognitive, emotional and social challenges for patients due to another person in a position of trust. Furthermore, randomization could not be guaranteed, because patients were able to choose by themselves if they agree to a cotherapists. For explanatory information further tests that measure potential reasons for the lack of efficacy of cotherapists are necessary. According to the current status of knowledge, the clinical use of cotherapists in this manner has not proven practical.