Effectiveness of Mentalization-based Therapy (MBT)

Inclusion Criteria: MBT Group: * Age 18-64 years. * Severe psychological symptoms, decreased functioning ability for long-term * Challenges with interpersonal relationships and emotional regulation * Patients willing to receive MBT * At least two of the following: * Depression (diagnosis codes: F31.3-F31.5, F32.0-F32.9, F33.3-F33.9, F34.1) or anxiety disorder (diagnosis codes: F40-F48) * Trauma background either as diagnosis or as need for treatment * Signs of personality disorder (suspected or diagnosed) TAU group: * Age 18-64 years. * Severe psychological symptoms, decreased functioning ability for long-term * Challenges with interpersonal relationships and emotional regulation * At least two of the following * Depression (diagnosis codes: F31.3-F31.5, F32.0-F32.9, F33.3-F33.9, F34.1) or anxiety disorder (diagnosis codes: F40-F48) * Trauma background either as diagnosis or as need for treatment * Signs of personality disorder (suspected or diagnosed) Exclusion Criteria: MBT Group: * Active substance use disorder (i.e., intoxication F1x.0, active dependence F1x.24, Continuous use F1x.25), a physiological withdrawal state F1x.3 and F1x.4, or psychotic disorder F1x.5). * Acute psychosis (defined as the recent onset of severe psychotic symptoms that interfere with functioning and are not yet in a therapeutic state. Non-acute psychotic symptoms are not exclusionary) * Disorder requiring inpatient treatment * Previously received MBT * Currently receiving psychotherapeutic treatment (previous psychotherapeutic treatment is not an exclusion) The exclusion criteria, therefore, do not exclude psychotic disorders or any other psychiatric illness (except substance abuse disorders). TAU group: * Active substance use disorder (i.e., intoxication F1x.0, active dependence F1x.24, Continuous use F1x.25), a physiological withdrawal state F1x.3 and F1x.4, or psychotic disorder F1x.5). * Acute psychosis (defined as the recent onset of severe psychotic symptoms that interfere with functioning and are not yet in a therapeutic state. Non-acute psychotic symptoms are not exclusionary) * Disorder requiring inpatient treatment * Previously received MBT * Intensive psychotherapy (e.g. rehabilitative psychotherapy or similar weekly long-term psychotherapy)