Generalized anxiety disorder (GAD) is a chronic condition characterized by an excessive and uncontrollable worry. GAD has a highly negative impact on all aspects of life, and the costs for society are considerable. Cognitive behaviour therapy (CBT), delivered face-to- face or online, has been shown to be effective in treating GAD. However, there are still room for improvement, with treatment content and format of delivery being two areas to further investigate. Internet-based treatments are often based on a generic CBT model of GAD and include treatment strategies such as cognitive restructuring and relaxation. Furthermore, the impact of therapist support has shown inconclusive results.

Overall, this thesis aimed to evaluate the effects of a new internet-based treatment for GAD, based on acceptance, mindfulness, and valued action, delivered with different types of support. Study I was a small pilot trial with a within-group design. The study included 16 participants diagnosed with GAD who received the newly developed treatment program with weekly therapist support. Statistically significant and large effect sizes were observed on self-rated worry at post-treatment, and the effects were maintained at a three-months follow-up. Study II included 103 participants diagnosed with GAD who were randomized to nine weeks of treatment with the treatment program and weekly support, or a waiting-list control group. Statistically significant moderate to large effects were observed on primary and secondary outcomes in favour of the treatment. The exception was a measure of quality of life, with no significant difference between the two groups. The treatment effects were maintained at a six-months follow-up. Study III was a pilot trial including 33 participants diagnosed with GAD. A within-group design was used to investigate the effects of the treatment program delivered with automated messages and support on demand. Significant and large within-group effects were observed on all outcome measures at post-treatment with the exception of quality of life, for which there was a small effect. Study IV was a pilot factorial design trial that compared the acceptance-based treatment program against a self-tailored treatment, as well as two types of support: scheduled support and support on demand. The study included 85 participants with GAD randomized to four different treatment groups. Significant moderate to large effects were observed in all treatment groups, with no statistically significant differences between the groups on self-rated outcome measures. Receiving scheduled support was rated as more positive than support on demand, and self-tailored treatment was rated as more positive than the acceptance-based treatment. Treatment satisfaction was high in all studies.

In conclusion, the studies indicate that an internet-based treatment based on acceptance, mindfulness, and valued action is a viable option in the treatment of GAD.

Generaliserat ångestsyndrom (GAD) är ett kroniskt tillstånd som kännetecknas av överdriven och okontrollerbar oro. Internetbaserad kognitiv beteendeterapi (IKBT) har visat sig vara effektiv vid behandling av GAD. Behandlingarna baseras ofta på en traditionell KBT modell med tekniker som kognitiv omstrukturering och avslappning. IKBT inkluderar ofta även stöd från en behandlare, men stödets inverkan på metodens behandlingseffekter har visat på blandade resultat. Det finns det fortfarande mycket att lära om hur behandlingarnas innehåll och grad av behandlarstöd påverkar utfallet.

Syftet med avhandlingen var att utvärdera behandlingseffekterna av ett nytt acceptansbaserat behandlingsprogram för GAD, förmedlat via internet, med endera veckovist stöd eller stöd vid behov. De fyra inkluderade studierna visar att behandlingen resulterade i signifikanta effekter på oro, GAD-symtom och komorbida depressiva symtom. Behandlingen var effektivare än kontrollgrupp (väntelista). Vid jämförelse med en aktiv behandling var effekterna likvärdiga. Att förmedla behandlingen med veckovist stöd eller stöd vid behov resulterade i jämförbara effekter på symptomskattningar. Dock slutförde fler som fick veckovist stöd hela behandlingen och de var även mer nöjda både med stödet och behandlingen. Behandlingseffekterna var jämförbara med tidigare IKBT-studier för GAD och deltagarna rapporterade hög grad av nöjdhet i alla studier. Sammanfattningsvis är acceptansbaserad internetförmedlad behandling ett effektivt alternativ vid behandling av GAD.