Clinical characteristics and treatment outcomes in body dysmorphic disorder

Abstract

Body dysmorphic disorder (BDD) is an early onset mental disorder characterized by a preoccupation with perceived flaws in physical appearance. Research on the presentation of the disorder is sparse, especially on young people with BDD. Furthermore, the availability of cognitive-behavior therapy (CBT) for the disorder is generally low, despite being recommended in treatment guidelines. The overall aim of this thesis was to further describe the clinical characteristics of BDD and to promote the dissemination of CBT among youth with BDD.

In Study 1, 600 individuals with an ICD-10 diagnosis of hypochondriasis or dysmorphophobia (i.e., BDD) (300 each) were randomly selected from the Swedish National Patient Register. Eighty-four medical files of individuals with hypochondriasis and 122 files of individuals with dysmorphophobia were received and used for analyses. Two independent raters assessed the validity and reliability of the diagnosis by performing an evaluation of the clinical charts. The inter-rater agreement regarding the presence or absence of a diagnosis was high for both disorders (95.2% for hypochondriasis and 92.6% for dysmorphophobia), and 80% of the hypochondriasis files and 91% of the dysmorphophobia files were considered ‘true positive’ cases. These results confirmed that the Swedish ICD-10 codes for hypochondriasis and dysmorphophobia are sufficiently valid and reliable to be used in register-based studies.

Following up on Study 1, Study 2 was a Swedish nationwide matched-cohort study of 2,833 individuals with an ICD-10 diagnosis of BDD, each matched with 10 unaffected individuals from the general population. During the study period, 466 (16.45%) individuals with BDD and 1,071 (3.78%) unexposed controls from the general population had at least one record of intentional self-harm. In adjusted models, an elevated risk of intentional self-harm was observed among individuals with BDD (IRR=3.37 [95% CI, 3.02-3.76]). Additionally, a total of 17 (0.60%) individuals with BDD and 27 (0.10%) individuals from the general population died by suicide (HR=3.47 [95% CI, 1.76-6.85]). In sum, individuals with BDD showed an increased risk of self-harm and death by suicide, compared to individuals without BDD.

In Studies 3 and 4 the aims were to explore the characteristics of a large cohort of adolescents with BDD, to evaluate the multimodal treatment outcomes of this cohort, and to examine potential predictors of treatment response. In our sample, we observed high rates of psychiatric comorbidity (71.5%), self-harm (52.1%), suicide attempts (11.0%), desire for cosmetic procedures (53.7%), and school dropout (32.4%). After receiving multimodal treatment consisting of CBT and medication when deemed necessary, 79% of the participants were classified as treatment responders and 59% as full or partial remitters. Encouragingly, BDD symptoms continued to improve up to one year after the end of the treatment. BDD symptom severity was identified as a predictor of treatment outcomes at post-treatment, but no consistent predictors were found at the one-year follow-up. The conclusion of these studies was that, while BDD in young people can be a serious and disabling disorder, often accompanied with substantial functional impairment and risky behaviors, multimodal treatment is effective in both the short- and the long-term when provided flexibly within a specialist setting.

Finally, in Study 5, we transferred the treatment protocol evaluated in Study 4 to an online version. The treatment was considered both credible and satisfactory and was associated with a large reduction in BDD symptoms. At the a priori primary endpoint (3-months follow-up), 74% of the participants were classified as responders and 63% as full or partial remitters, and the results continued to improve up to the 12-month follow-up. Furthermore, the average therapist support time was 8 minutes per participant and week. Nonetheless, risky behaviors typical of this patient group should be carefully monitored during treatment. CBT delivered in an online format with minimal therapist support is a feasible, potentially efficacious, and durable treatment for adolescents with BDD.

To summarize, this thesis concludes that BDD can be a severe and impairing mental disorder with several risks, including an elevated risk of intentional self-harm and death by suicide. It further suggests that face-to-face CBT for young people with BDD can be successfully implemented in specialist outpatient settings. To further increase treatment availability, CBT may also be delivered remotely, which has the potential to improve access to evidence-based treatment for youth with BDD.