Treating depression and its comorbidity : From individualized Internet-delivered cognitive behavior therapy to affect-focused psychodynamic psychotherapy

Abstract: The overarching goal of this thesis has been to enhance Internet-delivered psychological treatments for depression and its comorbidity. To this end, three randomized controlled trials (Study II, III and IV) with a total of 313 participants were conducted. A prevalence study (Study I) was also conducted to provide an up-to-date estimate of the prevalence of depression, anxiety disorders, and their comorbidity in the Swedish general population.Study I showed that more than every sixth individual in Sweden suffers from symptoms of depression and/or anxiety. Comorbidity between depression and anxiety was substantial and associated with higher symptom burden and lower health-related quality of life. Study II showed that a tailored Internet-based CBT protocol (ICBT) was effective in reducing symptoms of depression when compared to a control group. Among individuals with more severe depression and comorbidities, the tailored ICBT treatment worked better than standardized ICBT. Study III showed that a psychodynamic Internet-based psychotherapy was highly effective in the treatment of depression, when compared to a group who received psychoeducation and online support. In Study IV, an Internet-delivered affect-focused psychodynamic psychotherapy proved to have a large effect on depression and a moderately large effect on anxiety disorders.In conclusion, this thesis shows that in the context of treating depression and its comorbidity, Internet-delivered psychological treatments can be potentially enhanced by psychodynamic psychotherapy and by individualization.