A Phase II Randomized, Double-blinded, Placebo-controlled Parallel Group Trial to Examine the Efficacy and Safety of 4 Oral Doses of BI 1358894 Once Daily Over 12 Week Treatment Period in Patients 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.