Shared decision making (SDM) has been advocated as an appropriate approach for physician patient communication. Positive effects of SDM are e.g higher patient satisfaction, greater treatment adherence, lower decisional conflict and better clinical outcomes. The Section of Clinical Epidemiology and Health Services Research at the University Medical Center in Freiburg (Germany) is developing and evaluating a web-based interactive decision aid ("patient dialogue") to support shared decision making in cooperation with the Techniker Krankenkasse, a large German health insurance company. Both development and evaluation are conducted along the International Patient Decision Aid Standards (IPDAS).

The decision aid contains information on acute low back pain and depression and addresses insurance members who are facing a treatment decision in one of the indications. It aims at the development of patient competencies for participating in decision making, the support of constructive health behavior and patients' acceptance of evidence based treatment options.

In an RCT the decision aid will be compared to a regular patient information on a sample of N=500 patients in each group. Data collection will take place at three points of time: before and after use of the decision aid as well as 3 months later.

Inclusion Criteria:

• insurance members with acute low back pain or depression

Exclusion Criteria:

• insurance members without symptoms, with chronic back pain, with a bipolar disorder, relatives of people with symptoms