This study will determine whether dialectical behavior therapy and fluoxetine are more effective combined or alone in treating people with borderline personality disorder.

Borderline personality disorder (BPD) can be a serious and very complex condition. BPD affects 2% to 3% of the population and is more commonly diagnosed in young women. BPD is characterized by mood swings, impulsive behavior, difficulty controlling emotions, and acting out inappropriately either through self-harm or attempts of suicide. Other illnesses such as depression and anxiety are also very common in people diagnosed with BPD. Various treatments exist that aim to reduce self-harm and suicide among people with BPD. Dialectical behavior therapy (DBT), an outpatient behavioral therapy shown to help self-injurious patients with BPD, has become a popular treatment. Another useful treatment, the antidepressant fluoxetine, can help to regulate mood and diminish suicidal or self-destructive urges. Although combination treatments of DBT and fluoxetine are common, little research has been conducted on the effectiveness of this kind of combined treatment. The purpose of this study is to determine whether DBT and fluoxetine are more effective combined or alone in treating people with BPD.

All participants in this double-blind study will receive a psychiatric and medication evaluation prior to starting treatment. Participants taking psychiatric medications prior to the study will be slowly withdrawn from the medications over a period of 2 to 6 weeks. Psychological interviews and self-report questionnaires will be administered, taking approximately 5 to 10 hours to complete. Once all preliminary interviews and evaluations have been completed, each participant will be randomly assigned to one of the four following treatment groups:

• Group 1 will receive DBT and fluoxetine (Prozac). DBT teaches patients new skills to replace old coping strategies such as suicide attempts and self-injury. Participants will work with an individual therapist for 1 hour a week to learn these new skills. This group will also be expected to keep a weekly diary that will discuss their current mood; suicidal and self-harming urges; and possible use of medications, drugs, and alcohol. Once a week participants will engage in a 90-minute skills training group to review the skills learned during therapy. Homework will be assigned between sessions to review these new strategies and skills. Participants will meet regularly with a psychiatrist to receive fluoxetine, discuss any side effects, and adjust dosage if necessary.
• Group 2 participants will receive DBT and placebo medication.
• Group 3 participants will receive supportive therapy and fluoxetine. Supportive therapy is nondirective and focuses on strengths, coping abilities, and current areas of difficulty in life in an unstructured format. Participants in this group will meet with an individual therapist each week for 50 minutes. Patients will also be assigned to a psychiatrist to receive fluoxetine every other week.
• Group 4 participants will receive supportive psychotherapy and placebo medication.

All patients participating in this study will continue treatment for 12 months and will be evaluated bimonthly. After 12 months, participants will undergo neuropsychological testing to identify any changes that occurred over the last year. The clinical status of each participant will also be assessed at 18 and 24 months.

Inclusion Criteria:

• Meets criteria for DSM-IV diagnosis of borderline personality disorder
• History of at least one suicide attempt or self-mutilation episode 12 months prior to study entry
• Experiences continued urges to self-mutilate or attempt suicide
• Stable living situation
• Use of effective birth control if sexually active
• Clinically stable enough to tolerate placebo condition
• Not participating in other forms of treatment during the study

Exclusion Criteria:

• Any current organic mental syndromes, lifetime schizophrenic or bipolar disorders, psychotic disorders, or mental retardation
• Inability to complete psychiatric interview due to lack of cooperation or lack of comprehension
• Unable to tolerate fluoxetine or DBT
• Currently receiving treatment for an acute medical illness or other debilitating problem, including substance abuse or anorexia nervosa
• History of major depression lasting more than 3 months
• Current Hamilton depression score above 22 and not receiving treatment
• Pregnant or breastfeeding