Two other randomized controlled trials, investigating the effectiveness of dialectical behavior therapy, have presented intention to treat analysis of main outcomes (Turner, 2000
; Verheul et al., 2003
). Also Bateman and Fonagy (2001)
presented intention to treat analysis for data on follow-up of patients treated by partial hospitalization. We analyzed the data from the BOSCOT trial according to an intention to treat principle and declared our primary and secondary outcomes before having sight of the data. These factors, in combination with the numbers of participants included, blindness of assessors at follow-up, the high follow-up rate, and the use of case note and interview data sources, add emphasis to the provenance of the study findings.
On average patients in the CBT plus TAU, and TAU alone treatment groups had reduced suicidal behavior, attendance at A&E services and in-patient psychiatric days over the study period of two years. No significant differences between the randomized groups were noted in the components of the primary outcome though the odds ratios for suicidal acts indicate a 23% reduction in the odds of having at least one suicide attempt in favor of CBT compared with TAU and a 37% reduction in in—patient psychiatric hospitalization. Attendance at accident and emergency services reversed this trend with the CBT plus TAU group showing an increase in the odds of having an A&E attendance over the two years. However, while the number of participants in the CBT plus TAU group with at least one A&E attendance was larger (non-significantly), overall the average number of contacts with A&E was lower for the CBT plus TAU group. This pattern of result is repeated for the composite outcome, a combination of A&E service use, in-patient hospitalization, and suicidal behavior. Both groups show a decline in the composite outcome over the two years period with no significant advantage of one treatment condition over the other.
The use of accident and emergency attendance as one of the components of the primary outcome is problematic as individuals use A&E services for a variety of reasons, some of which were likely to be unrelated to the current study. We were unable to examine A&E contacts to determine if they were related to borderline psychopathology and behavior. Future studies, may wish to consider the utility of A&E contact as an outcome measure despite it being considered as one of the core features of borderline pathology (Linehan, 1993
Exploring the primary outcomes in terms of the overall quantity over the two-year period of the study, those who had the addition of CBT showed a significant reduction in the mean number of suicidal acts over the course of the study. In terms of secondary outcomes, significant differences between the treatment conditions were noted after one year by the Brief Symptom Inventory positive symptom distress index and, at two-year follow-up, on dysfunctional core beliefs and state anxiety. There were no differences at either 12 months or 24 months follow up in the outcome of scores on depression, trait anxiety, other psychiatric symptom indexes, interpersonal functioning, or on quality of life. Again all patients showed sustained and gradual improvement over the course of treatment and follow-up.
Although the addition of CBT to usual treatment did not result in significant differences on measures such as depression, social functioning, quality of life, psychiatric symptoms, other than PDSI, and interpersonal problems, all participants did show a general improvement on these measures. The addition of CBT to usual treatment was expected to produce enhanced cognitive change and a reduction in mood based symptoms and this was confirmed for change in beliefs but not for depression. The level of distress and dysfunction experienced by all trial participants remained relatively high, even at two years. This suggests that treatment, even if relatively brief, may be helpful to patients with borderline personality disorder but that the degree of benefit should not be overstated.
We previously stated that less than 15 sessions might be an inadequate amount of therapy and indicative of non-engagement (Davidson et al., 2006
). Our data on uptake of CBT therapy suggested that this group of patients are hard to engage in therapy in spite of efforts by therapists to keep them in active treatment. We believe that our patients had only the bare minimum amount of therapy required to benefit but this is an opinion and we have not examined this as a research question. Our trial participants were not overly selected—only four patients meeting inclusion criteria were not included in the trial because they either refused or lost contact before randomization—and unlike other studies, there was no attempt to screen out those who might be unsuitable or likely unwilling to comply with study requirements. We did not rule out comorbid problems such as depression or alcohol and drug abuse that are common in BPD.
Other studies have reported relatively high drop out rates from the experimental therapy, for example up to 37% (Verheul et al., 2003
). Determining drop-out from active treatment can be problematic as it depends on the definition of drop-out. We have presented the quantity of sessions of CBT that participants received. We had intended to give CBT according to a weekly then fortnightly schedule of appointments. In practice, some patients did not attend therapy at regular intervals over the 12 month therapy period. On the whole, patients did not drop out but continued to attend irregularly. The participants offered CBT in this trial therefore varied in the degree to which they received the schedule of CBT we considered might be optimal, though at least half (51%) received more than 15 sessions with just over one quarter receiving over 28 sessions (26%) of CBT over the year.
It is possible that some patients did not engage because they did not find the therapy helpful but ratings from patients who had at least three to five sessions of CBT on the Working Alliance Inventory suggest that both the patients and therapists view the experience of therapy to have been positive. Nonetheless, some patients simply did not attend. It is therefore more likely that the group as a whole represent the pattern of attendance that is often found in mental health clinics in the National Health Service (UK) (NHS), with some patients never attending (in our case, N = 3), some attending in a rather chaotic fashion, and around half attending sessions regularly.
Therapists varied in their degree of competence in delivering CBT. Shaw et al., (1999)
used a cut off score on the CTRS (of 39) below which therapists would not be considered as being competent enough to deliver CBT in a trial of CBT of depression. One out of the five therapists in this trial had a median score below this level (median rating of 37 on the CTRS), though individual scores from sessions of therapy rated varied with the session and the patient (range 27 to 49 on CTRS). This therapist had no previous formal training in CBT and may therefore have been significantly disadvantaged when trying to work with using a systematic structured therapy with patients with such complex problems. The variation in competence of therapists might be considered a limitation of the study. However, in this pragmatic trial we were unable to recruit volunteer “expert” doctoral level therapists and could only provide a minimum level of training, although regular and intensive supervision was provided throughout the trial. As such, the therapists in this trial are probably representative of qualified CBT therapists, though none would have considered themselves as particularly expert.
In conclusion, there is evidence that the addition of CBT to usual treatment has benefit in terms of reducing the volume of suicidal acts, reducing dysfunctional beliefs, state anxiety, and psychiatric symptom distress. The results of this study highlight the importance of measuring outcomes that are meaningful clinically, address the economic and health burden associated with this group of patients, and being able to assess outcome, even if the patient is lost to follow-up but not withdrawn consent. Commonly, longer-term follow-up of patients with borderline personality disorder indicate improvement over time, but again this is often not dramatic and psychosocial functioning often remains relatively poor (e.g., Zanarini, Frankenburg, Hennen, Reich, & Silk, 2005
). Our patients also continued to experience relatively high levels of dysfunction though they had clearly improved over the two-year period of the study.
It appears CBT can deliver worthwhile and clinically important changes in suicidal and self-harm behaviors, affective distress and dysfunctional thinking in representative samples of patients with borderline personality disorder. Therapists can be trained in CBT for personality disorders relatively easily particularly if they have previous experience and training in CBT, and, providing they are given appropriate levels of support and supervision. In this pragmatic trial, we investigated if CBT could deliver worthwhile benefit in real clinical settings and found that positive changes can be delivered in the community without recourse to intensive or lengthy treatment in highly specialized services. Future research may wish to carry out an explanatory trial that would investigate under what conditions CBT works more effectively, especially in terms of optimal therapist competence.