Clinical decisions in psychiatry should not be based on risk assessment.

OBJECTIVE Risk assessments that place patients in high or low risk categories have been widely adopted by mental health services in an attempt to reduce the harms associated with psychiatric disorders. This paper examines the effects of categorization based on the results of a risk assessment. METHODS The violence prediction instrument derived from the MacArthur Study of Mental Disorder and Violence was used to illustrate the nature and effects of risk assessment and the consequent categorization of patients. RESULTS The majority of patients categorized as being at high risk will not commit any harmful acts. CONCLUSIONS Patients who are classified as high risk share the cost of efforts to reduce harm in the form of additional treatment and restrictions, although the majority will not go on to commit a harmful act. Clinical decisions made on the basis of risk assessment also divert resources away from patients classified as low risk, even though a significant proportion do go on to a commit harmful act. We argue that psychiatric professionals should discuss the risks of treatment and of non-treatment with patients (or with their substitute decision-makers) and should maintain a duty to warn about the consequences of not having treatment. However, assessment of risk of harm should not form the basis for clinical decision making. We should aim to provide optimal care according to the treatment needs of each patient, regardless of the perceived risk of adverse events.