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.