A Study to Test Different Doses of BI 1358894 and Find Out Whether They Reduce Symptoms in People With Borderline Personality Disorder

This study is open to adults with borderline personality disorder. The purpose of this study is to find out whether a medicine called BI 1358894 helps to reduce symptoms in people with borderline personality disorder. Four different doses of BI 1358894 are tested in the study.

Participants are put into 5 groups by chance. Participants in 4 of the 5 groups take different doses of BI 1358894. Participants in the fifth group take placebo. Participants take BI 1358894 and placebo as tablets once a day. Placebo tablets look like BI 1358894 tablets but do not contain any medicine.

Participants are in the study for about 5 months. During this time, they visit the study site about 12 times and get about 6 phone calls. At the visits, doctors ask participants about their symptoms. The results between the BI 1358894 groups and the placebo group are then compared. The doctors also regularly check the general health of the participants.


Eligibility Criteria:
Inclusion Criteria:

* Patients meeting diagnostic criteria of borderline personality disorder (BoPD) per Diagnostic and Statistical Manual of Mental Disorders(DSM-5) at screening visit, confirmed by Structured Interview for DSM-5 Personality Disorder (SCID-5-PD).
* Zanarini rating scale for Borderline personality disorder (ZAN-BPD) of ≥ 9 at screening (Visit 1) and randomization (Visit 2), with question #2 Affective Instability score of ≥2.
* Male or female patients, 18-65 years of age at the time of consent
* Women of childbearing potential (WOCBP) able and willing to use two methods of contraception, as confirmed by the investigator, which include one highly effective method of birth control per ICH M3 (R2) that results in a low failure rate of less than 1%, plus one barrier method.

  --A woman is considered of childbearing potential (WOCBP), i.e. fertile, following menarche and until becoming postmenopausal unless permanently sterile. Permanent sterilization methods include hysterectomy, bilateral salpingectomy and bilateral oophorectomy. Tubal occlusion/ ligation is NOT a method of permanent sterilization. A postmenopausal state is defined as no menses for 12 months without an alternative medical cause.
* Signed and dated written informed consent in accordance with International Council on Harmonization (ICH) - Good Clinical Practice (GCP) and local legislation prior to admission to the trial.
* further inclusion criteria apply.

Exclusion Criteria:

* Current diagnosis of paranoid, schizoid, schizotypal and antisocial personality disorders, as confirmed by SCID-5-PD at screening visit.
* Lifetime diagnosis for schizophrenia, schizoaffective disorder, schizophreniform disorder, bipolar I disorder, or delusional disorder as confirmed by the SCID-5 at the screening visit.
* Any other mental disorder that is the primary focus of treatment in the last 6 months prior to randomization, as per the clinical judgement of the investigator.
* Inpatient stay or hospitalization due to worsening of BoPD within 3 months prior to randomization.
* Initiation or change in any type or frequency of psychotherapy for BoPD within the last 3 months prior to screening.
* Any ongoing use of psychotropic medications within 7 days prior to randomization or during the course of study.
* Any suicidal behavior in the past 1 year.
* Any suicidal ideation of type 4 or 5 in the Columbia Suicidal Severity Rating Scale (C-SSRS) in the past 3 months.
* further exclusion criteria apply.