feasibility of a novel process-based treatment for patients with psychosis

Conditions: Schizophrenia; Schizotypal Disorder; Delusional Disorder; Brief Psychotic Disorder; Shared Psychotic Disorder; Schizoaffective Disorder; Other Psychotic Disorder Not Due to A Substance or Known Physiological Condition; Unspecified Psychosis Not Due to a Substance or Known Physiological Condition; Manic Episode, Severe With Psychotic Symptoms; Bipolar Disorder, Current Episode Manic Severe With Psychotic Features; Bipolar Disorder, Current Episode Depressed, Severe, With Psychotic Features; Major Depressive Disorder, Single Episode, Severe With Psychotic Features; Major Depressive Disorder, Recurrent, Severe With Psychotic Symptoms

Summary: the purpose of this single-arm feasibility study is to develop and pilot test a novel process-based and modular group therapy approach for patients with acute psychotic symptoms in an inpatient setting.

due to the enormous economic and social costs of psychotic-spectrum disorders, increasing the effectiveness of treatment options has become an important subject for psychiatric research. latest findings in the field of psychotherapy for psychosis show some promising results for so-called process-based therapies (pbt) such as the metacognitive training (mct) and acceptance and commitment therapy (act) (barnicot et al., 2020). instead of trying to change the content of psychotic symptoms such as hallucinations and delusions, pbt directly address cognitive processes, which have been found to maintain the disorder's symptomatology (hayes et al., 2020). while mct focusses on changing patients' cognitive biases by inducing metacognition (moritz \& woodward, 2007), act works with psychological processes such as mindfulness, willingness and cognitive distancing (gaudiano \& herbert, 2006). there is a growing study base for pbt in a psychotic outpatient setting, research in non-ambulatory settings though is rare (barnicot et al., 2020). therefore, the aim of the current study is to develop and test the feasibility and safety of a new process-based group therapy program for acute psychotic patients. the five-week treatment approach will consist of three different modules combining interventions from both mct and act (module i: psychoeducation, module ii: metacognition, module iii: cognitive defusion). first preliminary effectiveness and process measures (panss, bprs, who-das, cgi, bcis and cfq) will also be included in order to inform the design of future research. thus, the study will give valuables insights in the feasibility and effectiveness of an innovative psychotherapy approach and breaks new ground in the field of psychotherapy research for psychosis.

Eligibility criteria:
inclusion criteria: * main diagnosis of a mental disorder with psychotic symptoms according to icd-10 criteria currently experiencing delusions and hallucinations (f20, f21, f22, f23, f24, f25, f28, f29, f30.2, f31.2, f31.5, f32.3, f33.3) indicated by diagnostic assessment of attending md * age between 18 and 70 years * informed consent to the study procedures and assessments (in written form) exclusion criteria: * severe neurological or internal concomitant diseases * iq \< 80; severe learning disability, brain damage or pervasive developmental disorder * missing eligibility for psychotherapy because of missing language skills/hostile or uncooperative behaviour. no further constraints will be imposed in order to collect data in a representative clinical sample.

Keywords: psychosis spectrum disorder process-based therapy modular psychotherapy group therapy acceptance and commitment therapy (act) metacognitive training (mct)