Decision analytical methods have been utilized and demonstrated to be of use for a broad range of applications in medical contexts, from regular diagnostic strategies and treatment to the evaluation of diagnostic tests and prediction models and benefit-risk assessments. However, a number of issues still remain to be clarified, for instance ease of use, realism of the input data, long-term outcomes and integration into routine clinical work. In particular, it is questionable whether clinicians are capable of providing the specific and high-quality input data that many of the prevailing methods require, since there is very often a lack of complete and precise background information. This is not least the case within psychiatric emergency care where the information available often is of a highly qualitative nature, but there is nevertheless a need for deliberate decisions. This article demonstrates, using a fictive but perfectly realistic case, how a decision support system can be useful in recommending courses of action within psychiatric emergency situations requiring rapid decisions despite a lack of complete and precise information.