Excessive worry in adolescents and adults : development and evaluation of theory-driven treatments

Abstract

Background: Worry is common among both adolescents and adults, and excessive worry is related to a number of mental health problems. Current pharmacological and psychological treatments for worry are moderately effective, and the processes involved in therapeutic change remain unclear. Building on theories of excessive worry could be a way forward in developing more streamlined and effective treatments. This thesis mainly concerns itself with two theories of worry: the intolerance of uncertainty model and the metacognitive model.

Aim: The overall aim of this thesis was to develop and evaluate streamlined psychological interventions for adolescents and adults, specifically targeting hypothesized causal mechanisms relevant in the maintenance of excessive worry. More specifically, the aims were (1) to develop a streamlined intolerance of uncertainty-focused treatment (IU-CBT) for adolescents with excessive worry, and explore its feasibility and preliminary efficacy in face-to-face and online-delivered formats, (2) to explore the experiences of the adolescents and their parents who had received online IU-CBT with parental involvement, and (3) to develop internet-delivered metacognitive therapy for adult worriers (I-MCT), evaluate its clinical efficacy, and explore the mediating effects of negative beliefs about worry in treatment.

Methods: Four studies (I-IV) were conducted within this doctoral project. To evaluate the feasibility and preliminary efficacy of face-to-face IU-CBT for adolescents, we conducted study I, an uncontrolled pilot feasibility trial (N = 12). The treatment protocol was subsequently transformed into an online version and its feasibility and preliminary efficacy was evaluated in a pilot feasibility study with a multiple-baseline design (N = 13; study II). In study III, eight adolescents and nine parents who had participated in study II were interviewed in a qualitative study and data were analyzed using thematic analysis. Study IV was a randomized controlled trial with mediation analysis where adult excessive worriers (N = 108) were randomized to either I-MCT or a wait-list control condition.

Results: In study I, there were no drop-outs or adverse events, and most families described high treatment satisfaction. The results showed large reductions in self-rated worry and secondary outcomes, and the effects were maintained at three-months follow-up. In study II, all but one adolescent followed through with the online treatment, and treatment module completion rates were high. We found medium to large reductions in self-rated worry, anxiety, depressive symptoms, and impaired functioning at post-treatment and the changes were maintained at one and three-month follow-ups. Study III showed that even though the online format posed challenges to the families and many would have appreciated some additional therapist-support, online IU-CBT for adolescents with excessive worry can be acceptable for both the adolescents and their parents. Exposure to uncertainty could be difficult but was also experienced as worthwhile and both adolescents and parents described the parental involvement in treatment as important for the adolescents’ treatment adherence. In study IV, treatment retention was high and I-MCT appeared to be acceptable to patients. Change in negative beliefs about worry mediated change in worry (more so than did change in depression), and large effects favoring I-MCT were observed. Effects were maintained after six and twelve months.

Conclusions: An IU-focused treatment for adolescents with excessive worry is feasible and potentially effective, when delivered face-to-face as well as online. I-MCT is also acceptable and effective for adults with excessive worry. Change in negative beliefs about worry appear to mediate change in worry outcomes in I-MCT, or put differently: if one does not believe that worry is dangerous or uncontrollable, one worries less. In conclusion, the findings lend further support to intolerance of uncertainty and negative beliefs about worry being promising treatment targets in novel interventions for excessive worry.