Patients with psychoses are randomized either to group treatment (ACT) or individual CBT for 18 sessions.

Since patients in the early stage of the illness seem to benefit more from CBT than patients with chronic conditions the present research will focus on patients with psychosis at the early stages of their illness. Patients with first episode psychosis from the Northern Stockholm Psychiatry (Midhagen) and the South West Stockholm Psychiatry (TIPS) will be included.

Scores on Alcohol Use disorder identification Test (AUDIT) and Drug Use disorder Identification Test (DUDIT) will be used as a covariate in order to control for the patients' s drug and alcohol use habits.

The study is single blind randomized controlled trials of manualized Cognitive Behavior Group Therapy (CBGT) versus an active treatment condition of individual CBT for patients with first episode psychosis. A total of 16 patients are enrolled and randomly allocated to either CBGT or to individual CBT treatment. Then 18 structured CBGT or individual CBT sessions approximately once a week will be offered. Three experienced CBT trained therapists will perform the therapies. Two therapists will be allocated to each group composed by approximately 5 patients.

The group therapies are conducted according to the Acceptance and Commitment Therapy (ACT) for psychosis manual (an 18 Session Group Therapy Protocol by Pearson A. & Tingey R.). The individual therapies are conducted according to non-manualized ordinary clinical procedure. The ACT manual is originally constructed for patients with chronic schizophrenia and has therefore been adapted by the therapists to be appropriate for patients with first episode psychosis. The therapists have taken a course in ACT and they receive ACT-supervision during the trial.

Assessments in both studies will be carried out at baseline, after therapy completion and 6 months later by an independent rater blind to group allocation and not involved in the treatment of the patients. The raters blindness will be measured.

Inclusion criteria: Diagnostic and Statistical Manual 5 (DSM-5):

• schizophrenia spectrum disorders:
• schizophrenia,
• schizophreniform psychosis,
• schizoaffective disorder)
• delusional disorder,
• brief psychotic disorder
• psychosis not otherwise classified.

Exclusion Criteria:

• Patients with drug abuse diagnosis
• organic brain injury,
• patients with grave somatic illness with secondary psychotic symptoms.