Psychotic disorders are associated with high levels of distress, limitations in quality of life, and a high risk of chronification for those affected. The treatment guidelines recommend combining the pharmacological treatment with psychotherapeutic methods, starting already in the acute phase. At the same time, there is little research evidence on which mechanisms of psychotherapy are most effective and best feasible for the acute setting. Therefore, the aim is to run a pilot study to test specific psychotherapeutic interventions for patients with psychosis on acute psychiatric wards.

The method of "Motivational Interviewing" is a well-known and established interviewing technique, which originally comes from the treatment of addictive disorders. In this study, it is used to strengthen the therapeutic alliance between patient and practitioner already in the acute phase of the disease, to increase adherence, and thus to achieve the overall goal of better integrating patients with pronounced positive symptoms into treatment. This appears to be extremely important, as non-adherence represents one of the greatest risks for chronification of the disease. The intervention will subsequently be evaluated in comparison to "treatment as usual".

Psychotic disorders are among the top ten causes of long-term disability and have a high chronicity potential and a high risk of invalidity. One-fifth of all patients with schizophrenia suffer from chronic symptoms and impairments, and the disease is associated with low long-term work performance, a high degree of all mental health care resources and high socioeconomic costs. These findings demonstrate the importance of sufficient treatment for psychotic disorders and, most importantly, point to a need for research so that more effective treatments can be developed in the future.

In the recent decade, various psychotherapeutic programs with cognitive-behavioral background have been developed for patients with psychosis, and their efficacy has been investigated. Meta-analyses have shown superiority of cognitive-behavioral therapy for psychosis over standard treatment, both in combination with antipsychotic medication and without. Many of the psychological approaches have focused primarily on treating the deficits associated with psychosis, as for example cognitive remediation or social skills training. However, these methods are not feasible in the acute setting and there are only a few psychotherapeutic instruments that can be used within a short period of time for inpatient treatment.

The guidelines for the treatment of schizophrenia recommend a combination of antipsychotic medication and psychosis-specific cognitive behavioral therapy. This includes all stages of the illness, also in the acute phase. The Swiss Society for Psychiatry and Psychotherapy (SGPP) has stated in its treatment guidelines for schizophrenia that "our group recommends a structured psychotherapeutic approach even in the acute phase of the disease. The best evidence currently exists for cognitive-behavioral approaches, […]. In any case, the psychotherapeutic procedure must be adapted to the circumstances of the acute phase and there is an urgent need for research on how this can be arranged in the setting of an acute ward.". Despite this explicit recommendation, to our knowledge there have been no studies that have systematically investigated this in the acute setting and results of which could therefore inform future treatment recommendations. As proposed by the SGPP, the aim is to systematically test and evaluate psychotherapeutic interventions in the setting of an acute care unit in an initial pilot trial.

Therapeutic alliance during the acute phase of psychotic illness is one of the most pressing obstacles for successful long term recovery. In order for patients to accept much-needed medication and psychosocial therapy and not drop out prematurely, intrinsic motivation to adhere to therapy is crucial. Motivational Interviewing is a method, that has been developed and evaluated over the last three decades and that shows promising results, not only for patients with addiction but also for other patients who struggle with compliance and ambivalence towards treatment and change of behavior.

It is well known from clinical experience that patients are offered psychotherapy only late during the course of hospitalizations and not when it is highly needed - during the acute phase of their illness. Accordingly, there is a clear gap in the literature as to which interventions are particularly useful in this challenging yet crucial phase of the illness.

Inclusion Criteria:

• Informed consent as documented by signature
• Male and female patients from inpatient units of the Psychiatric University Hospital of Zurich
• ICD-10 diagnosis of psychosis (F2.x)
• Fluent in German and able to understand the instructions

Exclusion Criteria:

• Organic schizophrenia-like disorder (ICD: F0.6)
• Drug or alcohol abuse during treatment
• Previous enrolment in the current study
• Enrolment of the investigator, his/her family members, employees and other dependent persons
• During study: Complete stop of taking antipsychotic medications