The Modulatory Role of Communicated Treatment Rationale on Treatment Expectation Effects in Depression.
Condition: Condition: Major Depressive Disorder (MDD)
MeSH terms: Depression; Depressive Disorder; Depressive Disorder, Major
Study type: Interventional

Summary: 
      Placebo groups in clinical trials on depression show impressive improvements. Yet, there is
      little research on the mechanism underlying this effect. The aim of this study is to assess
      how patients' treatment expectations modulate the placebo treatment effects.

      We expect that patients' treatment expectation determines placebo responses and treatment
      outcomes, and that this expectation is influenced by the disorder explanations (information
      about the illness models) typically provided during the initial medical encounters that
      precede treatment.

      In the study we aim to manipulate depressed patients' expectations by providing two different
      clinician-delivered illness and treatment rationales (biological/ psychological). Patients
      will then receive placebo treatment (pharmacological/ psychological), that is either
      congruent or incongruent with the previously communicated treatment rationale.

      Hypotheses:

        1. Providing a treatment-congruent treatment rationale leads to a better outcome than
           providing treatment-incongruent rationales.

        2. Treatment-congruent explanations reduce the risk of side effect development, in
           particular in the medication arm.

        3. Inter-individual differences in the effect of provided treatment rationale are
           associated with pre-treatment experiences and expectations, depression severity and
           comorbid anxiety.
    


Intervention name(s): Biological illness and treatment rationale; Psychological illness and treatment rationale; Active pharmacological placebo; Active psychological placebo
Intervention type(s): Behavioral; Behavioral; Drug; Behavioral
Intervention description(s): Depression is described as a brain disorder and the role of monoamine, brain structures, and brain functions are reported as central mechanisms of relevance for its etiology and treatment. Biological processes are illustrated using typical charts and visualizations. Psychological influences are mentioned, but only as a byproduct of the disorder.; Depression is described as a psychological disorder resulting from emotion regulation deficits. The suppression of emotions receives a special role in explaining depression. The psychological processes are illustrated using charts and visualizations. Biological aspects are mentioned, but only as a byproduct of the disorder.; The active placebo pill does not have direct effects on the brain. Buscopan (butylscopolamine, 10 mg daily, 1 pill in the morning) does not cross the blood-brain barrier, yet induces some smaller side effects that resemble those of antidepressants (e.g., mouth dryness, fatigue, nausea). Treatment duration is 4 weeks. The rationale is briefly explained to participants as "stimulating the biological balance in humans with depression, using a well-tolerated drug similar to Buscopan, which is well-known from pain treatments.; "Emotional writing" consists of writing about emotional experiences (4 sessions, one per week, 30 minutes each). The study instructor will be present displaying standard psychotherapeutic attitudes but will not read the participant's notes. The rationale for this treatment is briefly explained as "improving the dealing" with emotions to achieve a psychological balance in humans with depression.
Allocation: Randomized
Intervention model: Parallel Assignment
Masking: Triple (Participant, Care Provider, Outcomes Assessor)
Primary purpose: Basic Science
Keywords: Placebo effect; Treatment rationale; Depression; Expectations