ABSTRACT

Borderline personality disorder is one of the complex mental disorders. It also features impulsivity and self – harming behaviors. The objective of this research was to investigate and compare the effectiveness of DBT with that of ST in reducing the severity of clinical symptoms (i.e., disruptive communication, emotional deregulation and behavioral deregulation) of borderline personality disorder patients.The sample consisted of 45 borderline personality disorder patients selected based on diagnostic and statistical manual of mental disorder-fifth edition(DSM-5), clinical interview and borderline personality disorder severity index(BPDSI).Moreover, they were matched concerning age, educational status, sex, not suffering from acute physical, mental disorder and other criterion considered in this research. Then, they were randomly divided into threegroups (i.e., 2 experimental groups and one control group). The instrumentswere included clinical interview and borderline personality disorder severity index (BPDSI). After pre testing, the first experimental group received12 sessions of DBT and the second experimental group (ST) was administered 12 sessions of (ST), but the control group did not receive any intervention,then, post - test was taken from both groups. After 6 months, a follow-up test was administered.The results revealed that (ST) and (DBT) reduced the symptoms of borderline personality disorderincomparison with pre-test and control group(P<0.001). The effectiveness of (DBT) in disrupted communication was significantly higher than (ST)in post-test and follow-up periods.However, there was no significant difference between (DBT) and (ST)in terms of both emotional and behavioral deregulations. In addition, (ST)was more effective than (DBT)in reducing emotional deregulation, but there was no significant difference between them.Moreover,in follow-up period, the (DBT) was significantly more effective in reducing unstable interpersonal relationships and suicidal symptoms than(ST).However, the (ST)was more effective in reducing unstable emotional behaviors.