Disclosure of incidental constituents of psychotherapy as a moral obligation for psychiatrists and psychotherapists.

Informed consent to medical intervention reflects the moral principle of respect for autonomy and the patient's right to self-determination. In psychotherapy, this includes a requirement to inform the patient about those components of treatment purported to cause the therapeutic effect. This information must encompass positive expectancies of change and placebo-related or incidental constituent therapy effects, which are as important as specific intervention techniques for the efficacy of psychotherapy. There is a risk that informing the patient about possible incidental constituents of therapy may reduce or even completely impede these effects, with negative consequences for overall outcome. However, withholding information about incidental constituents of psychotherapy would effectively represent a paternalistic action at the expense of patient autonomy; whether such paternalism might in certain circumstances be justified forms part of the present discussion.