The DBT-A, as evaluated in this study, is based upon a manual which has been translated and modified for use in Germany by our study group. Thus, the results of this study represent the first experiences gained with DBT-A in German-speaking countries. Our study aimed at investigating whether suicidal and non-suicidal self-injurious behavior decreased in the treated adolescents, whether the adolescents completed the therapy program successfully and whether psychosocial adjustment and psychopathology of patients improved and consistently remained this way over a one-year period up to follow-up.
Adolescents with suicidal and non-suicidal self-injurious behavior and traits of a borderline personality disorder are considered to be a patient group which is difficult to treat. Therefore, the therapy drop-out rate in this patient group is known to exceed 60% . The fact that a therapy program which takes place twice a week and stretches across 16 to 24 weeks is apparently able to bring about positive changes in behavior, psychosocial adjustment and in the distress associated with the adolescents' symptoms, is especially motivating. Furthermore, the majority of patients are generally able to complete therapy regularly.
By using this therapy, our investigation group was able to show a stable reduction of suicidal and non-suicidal self-injurious behavior over the course of one year - as considered being the primary target of DBT. Our results validate evaluations from the US, which were able to prove a reduction of suicidal and non-suicidal self-injurious behavior under the treatment with DBT in comparison to controls. This applies to both female adults and adolescents diagnosed with BPD symptoms [6, 7, 25]. In a 10-year prospective follow-up study on adult patients with BPD by Zanarini et al. , 50% of patients recovered from borderline personality disorder which was defined as a remission of symptoms as well as social and vocational functioning during the previous two years. It has to be emphasized that certain symptoms of BPD, e. g. non-suicidal self-injury, suicide gestures and suicide attempts, are easier to remediate with medication, psychotherapy or a combination of both . Furthermore, a 1-year open trial by Goldstein et al. could demonstrate a significant improvement in suicidality and non-suicidal self-injurious behavior in adolescents with bipolar disorder . However, these very promising results on the efficacy of DBT are challenged to some extent as Linehan's biosocial theory on BPD - suggesting that individuals with BPD have biologically based abnormalities in emotion regulation contributing to more intense and rapid responses to emotional stimuli (invalidation in particular) - has not fully been proved yet . Woodberry et al. have found neither self-report nor physiological evidence of any hyperarousal in BPD groups .
The second important goal in the hierarchy of DBT is to keep patients in therapy. In our study, the drop-out rate amounted to 25%, which ranks slightly below the drop-out rate of 38% as found in a comparable study by Rathus and Miller [7, 9]. Taken together, with completion rates between 62% and 90%, this corresponds with the current literature on DBT [7, 9]. Our drop-out rate still ranks far below Rathus' and Miller's control group's drop-out rate of 60%, which underwent unspecific `treatment as usual`. Remarkably, the patients treated with DBT had a higher impact of psychiatric diagnoses before the start of therapy than the control group .
In accordance to comparable studies [6, 7, 25], our patient group exhibited a reduction of the length of psychiatric inpatient treatment during therapy.
After therapy, patients appear to be dealing with the various and sensitive demands of adolescent evolution more easily. This hypothesis is also based on the improvement of both the Global Level of Functioning and the reduction of the need for treatment as assessed by the therapist.
Patients dropping out of therapy showed more current psychiatric DSM-IV axis-I diagnoses at the beginning of therapy (i. e. on average 1.3 diagnoses per patient), rather than the patients who ended therapy regularly (i. e. 0.9 diagnoses per patient). This tendency increased one year after the end of therapy. At that time, a total of nine current psychiatric DSM-IV axis-I diagnoses were assessed. Out of these, six diagnoses (67%) occurred in the three patients having dropped out of therapy while the nine patients ending therapy regularly were diagnosed with merely three diagnoses (33%).
At the beginning of therapy, the diagnosis of BPD was assessed for 83% of the adolescent patients, whereas one year after the end of therapy, this diagnosis persisted in only 17% of patients. Out of the nine patients ending therapy regularly, only one patient was still suffering from BPD according to the diagnostic criteria of DSM-IV. one year after therapy. This corresponds to a remission of BPD one year after therapy in six out of seven patients (86%) who ended therapy regularly. In comparison, Zanarini et al. [26, 29] have stated similar remission rates under different kinds of therapy (35% after two, 49% after four, 69% after six years and 93% after 10 years) in a 10-year follow-up study on adult patients suffering from BPD.
The distinct reduction of suicidal and non-suicidal self-injurious behavior during therapy is reflected in the rating of the DSM-IV borderline criteria assigned to these symptoms. The adolescents made clear progress in the DSM-IV criteria "unstable and intense interpersonal relationships", "identity disturbance" and "impulsivity". These criteria were explicitly discussed in the multi family skills training group and solution strategies were developed in the training modules Distress Tolerance Skills and Emotion Regulation Skills. The adolescents' significant improvements are in line with the improved scores on SCL-90-R Interpersonal Sensitivity and Depression subscales. Distinct progress occurred in the DSM-IV criterion "frantic efforts to avoid real or imagined abandonment", indicating that patients generally improve in getting along with themselves and their environment and have more self-confidence after the end of therapy. Patients dropping out of therapy met more DSM-IV criteria per patient when starting therapy than patients who ended therapy regularly. During the observed period, there was less reduction of fulfilled DSM-IV criteria per patient in those patients who dropped out of therapy.
The number of fulfilled DSM-IV criteria for BPD per patient as well as the number of current psychiatric DSM-IV axis-I diagnoses before the start of therapy could thus provide a predictive statement as to whether a particular patient will be able to pass through therapy completely, and as to how far the implementation of therapy will make sense.
Under therapy, self-evaluation (SCL 90-R, YSR, DIKJ) in particular showed improvements in the global scores of psychopathology, persistent over the year following therapy. In self-evaluation, the symptoms of depression (SCL 90-R, YSR, DIKJ), anxiety (SCL 90-R, YSR), social withdrawal (YSR) and attention problems (YSR) decreased in particular. Rathus and Miller  have found similar results in SCL 90-R. In addition, they have assessed an improvement of social contacts. In our study, this effect kept limited to the year following therapy.
The adolescents' quality of life, measured by using ILC, improved clearly from the start of therapy to one year after therapy.
Assessment by the parents showed an improvement of the quality of life, both during therapy, and in the year following therapy. Symptoms of psychopathology in general diminished - mostly in the year after therapy.
All in all, the three patients who dropped out of therapy presented an amelioration regarding their situation prior to therapy. In one patient, the symptoms vanished quickly. Pathology improved so much after having passed the first skills section, that the adolescent and his family abandoned further treatment. One year after therapy, one patient showed slightly reduced pathology. In one patient, pathology persisted undiminished after therapy dropout. The influence of incomplete participation on the development of patients remains unclear.
Limitations of the present study are mainly related to its design. The study lacks a control group by means of which the strong therapeutic effects over the course of therapy could be compared to controls. The fact that the reliability and validity of the diagnosis of BPD in adolescents as well as its measurements have not been evaluated sactisfactorily yet, limits the present study results to some extent. As assessments were conducted by therapists, a potential bias cannot be ruled out.