The aim of the present single-blind randomized-controlled therapy study is to assess the efficacy of a new form of Cognitive Behavioral Therapy for delusions with a focus on emotion regulation, improvement of self-esteem and sleep quality (CBTd-E).

Numerous meta-analyses have found Cognitive Behaviour Therapy for psychosis (CBTp) to be effective. The effect sizes that are achieved for positive symptoms in addition to antipsychotic treatment vary between small to medium. However, the effect sizes for changes in delusions are somewhat lower. Thus, it could prove beneficial to tailor CBTp interventions more precisely to the processes that are relevant to delusions. Empirically derived models of the formation and maintenance of delusions postulate an important role of cognitive biases, emotional factors and self-esteem. Additional studies have demonstrated the relevance of impaired sleep to delusions. Nevertheless, CBTp interventions that aim to change delusions tend to focus mainly on reasoning bias.

The results of several uncontrolled pilot studies that focused primarily at improving emotional factors, quality of sleep and self-esteem in patients with delusions indicate that changes in these factors have the potential to reduce delusions. However, in these studies the singular interventions were short and were not implemented into a broader therapy rational. It can thus be assumed that a combination of CBT-interventions within a broader therapy rational might have an even greater impact on delusions.

The aim of the present single-blind randomized-controlled therapy study is to assess the efficacy of a new form of Cognitive Behavioral Therapy for delusions with a focus on emotion regulation, improvement of self-esteem and sleep quality (CBTd-E) that will be applied in 25 individual sessions. Moreover, the study aims to test whether the efficacy of CBTd-E is mediated by the postulated processes. The main hypotheses are:

1. Baseline differences: in comparison to healthy controls, patients with schizophrenia show more pronounced problems in emotion regulation, a reduced sleep quality and a lower and less stable self-esteem.
2. Efficacy of CBTd-E: patients with acute delusions who receive CBTd-E show a more pronounced reduction of delusions (primary outcome), as well as a more pronounced reduction of positive symptoms, depression and general psychopathology, a stronger improvement in general and social functioning and will receive lower doses of antipsychotic medication (secondary outcomes) at post-treatment.
3. Mediation: the effect of CBTd-E on change in delusions is mediated by a) improved emotional stability and ability to regulate one's own emotions, b) improved sleep quality, c) improved and more stable self-esteem.

In addition to questionnaires and interviews, behavioral paradigms, psychophysiological assessments and electronic diaries will be used to test the hypotheses. If we can demonstrate that CBTd-E reduces delusions, this would provide us with a more acceptable and feasible therapy for treating delusions.

Treatment Group:

Inclusion Criteria:

• Diagnosis of schizophrenia, schizoaffective disorder, delusional disorder (DSM-5 diagnosis)
• Delusions present in the last three months (score of at least three in three out of six PSYRATS scores)
• problems in at least two out of three possible mediators: sleep problems (ISI sum score > 7), low self-esteem (score > 3in the BCSS negative self scale) and/or problems in emotion regulation (score in all items < 4)
• fluent in German language
• agree to participate
• estimated general intelligence of at least 70 in the German Mehrfachwahlwortschatztest (MWT-B)
• no present suicidality

Exclusion Criteria:

• acute suicidal tendency
• comorbid diagnosis of borderline personality disorder and/or substance use disorder in the last six month
• taking of Benzodiazepines