There is a lack of psychological treatments within inpatient psychiatric care while there is support for active psychological interventions having an effect on psychiatric problems. The purpose of the present feasibility study is to test whether a psychological treatment based on Cognitive Behavioral therapy (CBT) and Acceptande and Commitment therapy (ACT) for patients in psychiatric inpatient care is acceptable, understandable, helpful and effective both for patients and the staff who carry out the treatment. The therapist in the project will receive training and on-going supervision in a CBT-manual created within the research group.

The main questions the study aims to answer are:

1. Is cognitive behavioral therapy perceived as acceptable, comprehensible and helpful for patients in psychiatric inpatient ´care, when given by nursing staff in inpatient care?
2. Is cognitive behavioral therapy perceived as acceptable, understandable and helpful to the nursing staff who provided the treatment intervention?
3. Is cognitive behavioral therapy effective in reducing psychiatric symptoms such as depression, anxiety, and perceived health status for patients in psychiatric inpatient care when provided by nursing staff?

Participants are nursing staff from eight psychiatric inpatient wards and patients. The training consists of a two day workshop in the CBT manual followed by eight group supervision sessions parallell with patient treatment.

The patients are offered a CBT manual based psychological intervention with planned four treatment sessions but these can be flexibly prolonged to more sessions for repetition for patients staying for a longer period of time.

The study is a quasi-experimental design. Randomization takes place at ward level. The wards will be twin-matched based on patient problems and then randomized to treatment as usual (control group) or treatment as usual plus a CBT intervention (experimental group). Eight wards are included. Four wards will thus act as a control group and four wards as an experimental group. All within inpatient-care at Region Stockholm. The study aimed to include a total of 230 participants during 2020-2023. With a distribution ratio of 1:2, 77 participants are allocated to the experimental group and 153 participants to the control group, calculated on the basis of an expected effect size of 0.35 and a power of 0.8.

Patients who fulfill the inclusion criteria are informed about the study orally and in writing and are offered participation. Informed consent is collected upon offer of participation in the study. Patients are included consecutively as long as the ward and therapists have the available resources to accept more participants. Patients fill in self-report forms in connection with the usual enrollment and discharge routine. The self-report forms are questions about anxiety symptoms (GAD-7); perception of health (EQ-5D); depression symptoms (PHQ-9): experience of the intervention; Behavioral Activation Depression Scale-Short Form (BADS-SF); patient satisfaction. For the qualitative part with in-depth interviews, approx. 20 nursing staff are recruited. Semi-structured interview guide for nursing staff is created.

Inclusion criteria:

• Meet criteria for and are enrolled in psychiatric inpatient care.
• Agree to participate in the study.
• Assessed to be stable enough to participate in a conversation after a routine ward medical assessment (do they understand what they are agreeing to/not to, can communicate, etc.)

Exclusion criteria:

* Other ongoing intensive psychotherapy (e.g. in outpatient care that continues during the psychiatric inpatient care stay).

IPD for this data set can not be made available on the individual participant level due to consent given by participants during project time since 2020. Although data on group level including measures of variance and details of statistical analysis plan will be shared to researchers on request.