Evaluating Process of Change in Cognitive Behavioral Therapy and Acceptance and Commitment Therapy for Depression

This study will compare two psychological treatments for major depressive disorder (MDD): cognitive-behavioral therapy (CBT) and acceptance and commitment therapy (ACT). Both treatments are well-studied and supported by evidence as effective options for people experiencing depression. These treatments will be delivered in an online group format via Zoom.

The study will enroll up to 100 participants with depression. Half of the participants will receive online group CBT and half will receive online group ACT. There will be up to 10 members in each group. For both conditions, treatment will be provided over 8 weeks, with a 6-month follow-up period. Enrollment will be ongoing and groups will occur simultaneously.

Potential participants are asked to complete an initial screening and an intake evaluation to determine eligibility. They will then receive 8-weeks of treatment. Participants will complete self-report questionnaires throughout their time in the study.

Some of the most powerful tools to combat depression come in the form of psychotherapies, including Cognitive Behavioral Therapy (CBT) and Acceptance and Commitment Therapy (ACT). While both treatments have been found to be generally effective in treating depression, they take fundamentally different treatment approaches. In CBT, clients learn techniques to challenge and change maladaptive thought and behavioral patterns. In ACT, clients learn techniques to accept their negative internal experiences and commit to action in line with their values. Despite being among the most effective treatments for depression, both CBT and ACT have a response rate of about only 50%. It is believe there are two key reasons investigators have not been able to improve these response rates. First, very little is known about which specific therapeutic skills are effective in these treatment packages. For example, do cognitive or behavioral change skills lead to therapeutic change in CBT? In ACT, do acceptance or change skills lead to therapeutic change? Second, it is not known which specific treatments or therapeutic skills work better for different individuals. Every individual has diverse needs, and therefore individuals may benefit differently from different treatment packages or from specific skills within each package.

Therefore, investigators plan to run a randomized controlled trial comparing CBT and ACT for depression in order to investigate which specific therapeutic skills are effective in these treatment packages. This approach will also allow investigators to identify predictors of differential response to treatment packages and specific treatment skills.

Upon joining the study, participants are asked to complete surveys for one week prior to starting treatment and again for one week once treatment is completed. During treatment, they are asked to complete surveys throughout the 8 weeks of therapy. Following the 8-week treatment, participants are asked to complete monthly follow-up surveys for 6 months.

There are three main objectives in this study. The first is to compare processes of change across the two treatments (i.e., what works in specific treatments?). The second is to determine client variables that predict differential treatment response (i.e., which treatment works best for a given client?). The third is to evaluate potential moderators of differential response to any specific skills across the treatments (i.e., which specific therapy skill works best for a given client?)

Eligibility Criteria:
Inclusion Criteria:

* diagnosis of major depressive disorder (MDD) according to DSM-V criteria (APA, 2013)
* 18 years of age or older
* access to a private location with a stable internet connection and a working video camera
* lives in California
* able to understand and speak English
* able and willing to give informed consent

Exclusion Criteria:

* current diagnosis other than MDD if it constitutes the predominant aspect of the clinical presentation and if it requires treatment other than that being offered
* clear indication of secondary gain (e.g., court ordered treatment)
* current suicide risk or significant intentional self-harm in the last six months sufficient to preclude treatment on an outpatient basis.