In the context of an interview study concerned with self-determination in psychiatric patients, this paper describes the preconditions for and consequences of self-determination from the point of view of psychiatric patients themselves. The data were collected in semi-structured interviews with long-term psychiatric patients (n=72) and analysed using the method of content analysis. Responses on the preconditions for self-determination were grouped into three categories: firstly, there were those who said that reference to self-determination in the case of psychiatric patients is nonsense; secondly, there were those who said that self-determination requires no preconditions; and thirdly, there were those who said that there are certain preconditions, such as the ability to think and make decisions, activity, obedience, and illness. Both positive and negative consequences were identified in situations where self-determination is maintained, but only negative consequences in situations where self-determination is lost. On the basis of these tentative results, self-determination seemed to be relevant in psychiatric nursing. We are continuing to develop and test an instrument for the evaluation of the opportunity for self-determination in clinical practice.