Social Learning Trial: Using Patient and Clinician Testimonials to Modify Treatment Expectations and Placebo Treatments in Depression

Research has shown that treatment expectations play a major role in the course of mental disorders and that positive expectations have a beneficial impact on treatment outcomes. Expectations can develop in different ways, whereby an emerging body of research has shown that social learning plays a significant role in this process. To date, most studies have investigated the impact of social learning on treatment expectations in the context of pain relief. Little is known about the impact of social learning in the psychotherapeutic treatment of depression. Therefore, this study investigates whether treatment expectations regarding the treatment of depression can be modulated via social learning, i.e., showing positive treatment testimonials.

Hypotheses:

H1: The investigators predict that individuals who are provided with treatment testimonials (experimental groups) show a greater change toward positive treatment expectations compared to individuals who do not view such testimonials (control groups).

H2: The investigators predict that individuals provided with treatment testimonials will, compared to the control groups, show a greater change in secondary outcome variables in the following ways: a greater decrease in perceived uncertainty/ barriers; a greater decrease in stigma/ negative attitudes toward psychotherapy; a greater increase in intentions to seek therapy; a greater willingness to try the specific technique described in the videos.

H3: Inter-individual differences in the effect of provided testimonials are associated with pre-existing factors: level of depressive symptoms; intolerance of uncertainty; treatment experience; locus of control; general self-efficacy; dispositional optimism and cognitive immunization tendencies.

Exploratory questions:

1. An exploratory aim of this study is to assess whether viewing different types of testimonials (clinician delivered; patient-delivered; combination of both) has differential effects on treatment expectation change.
2. Furthermore, the investigators want to assess whether implicit treatment expectations change in a similar pattern as explicit treatment expectations.
3. Based on the results of H1 and H2, the investigators aim to assess possible mechanisms of change: e.g. assess whether a change in treatment expectations is mediated by a decrease in perceived uncertainty or a change in stigma/ attitudes toward therapy.