Abstract: Objective To study the characteristics and related factors of self-injury and suicide in bipolarⅠand bipolarⅡdepression. Methods 97 hospitalized patients with bipolar depression met the diagnostic criteria of DSM-5 bipolar disorder as major depressive episode were selected, including 43 cases of bipolarⅠtype(44.33%)and 54 cases of bipolarⅡtype(55.67%).The frequency of self-injury, ways of self-injury, suicidal ideation, times of suicide and ways of suicide were evaluated by questionnaire. The clinical symptoms of the patients were assessed using the Hamilton Depression Scale-17, Hamilton Anxiety Scale and 32-item Hypomania Checklist. The diagnosis items of borderline personality disorder in the DSM-Ⅳ-TR Axis Ⅱ Disorder Clinical Standard Examination were assessed. Results 77.78% of bipolarⅡpatients had significantly higher rate of self-injury and suicide than 39.54% of bipolar I patients(χ²=14.693,P<0.01).The proportion of bipolarⅡtype with self-injury was 64.82%, which was significantly higher than that of bipolar I type(23.26%)(χ²=18.093,P<0.01).The suicide frequency of bipolarⅡdepression patients was 1(0,1.25)times, which was significantly higher than that of bipolar I depression patients 0(0,1)times(Z=2.289,P=0.022).The ways of self-injury in bipolar Ⅱ depression patients were significantly higher than those in bipolar I depression patients in (1) cutting themselves with knives and sharp tools,(2) picking or scratching themselves, pulling their hair forcibly,(3) biting themselves forcibly(P<0.05).Patients with bipolar Ⅱ depression were more likely to commit suicide by taking medication and jumping off(P<0.05). Borderline personality was higher in bipolar Ⅱ(62.96%)than bipolar Ⅰ(18.60%)(χ²=19.185,P<0.01). Conclusion The incidence of self-injury and suicide in bipolarⅡdepression patients is higher than that in bipolar I depression patients. The way of self-injury and suicide is obviously different between them. The problem of self-injury and suicide in patients with borderline personality is prominent.

Key words: bipolar disorder, self-injury, suicide, borderline personality disorder, Hamilton Depression Scale