Braining: Implementation of Physical Exercise for Patients in Specialist Psychiatry

The goal of this clinical trial is to compare Braining, a physical exercise lifestyle intervention in psychiatric care, with structured advice on physical exercise. The main questions are: * does Braining lead to increased physical exercise compared to structured advice on physical exercise? * what effect does Braining have on mental and physical health, quality of life and functional level compared to structured advice on physical exercise? The participants will join a twelve weeks long study period with clinician led exercise classes up to three times per week. Before and after the study period they will leave blood tests, take part in a mental and physical examination and fill in assessment scales. To measure physical activity, the participants will carry an accelerometer, a device that measures steps and acceleration. After six and twelve months, the participants take part in the same measurements. The control group takes parts in the same measurements and follow up, but instead of having clinician led exercise classes, they will exercise on their own during the twelve weeks study period.