background Formally, incompetence implies that a patient cannot meet the legal requirements for informed consent. Clinical practice shows that psychiatric patients with poor insight do not always consent to treatment, leaving the clinician with an untreated patient with a bad prognosis and few or no options for intervention.
aim To review the scientific literature on 1. The relationship of competence and insight in patients with psychiatric disorders, 2. How competence and insight are connected in these patients and 3. Whether there are differences in competence and insight among patients with different disorders.
method A search in PubMed/Medline using the terms ‘competence’, ‘competency’, ‘capacity’, ‘decision making’ and ‘Maccat’, combined with both ‘insight’ and ‘psychiatry’.
Articles in English based on empirical research, available in February 2010, were included. Articles were assessed on relevance criteria by two independent reviewers. Study design, study population, variables and outcomes were extracted.
results Seven articles were included, on studies of psychiatric inpatients and outpatients and of psychotic and non-psychotic patients. All studies used the MacArthur Competence Assessment Tool for Treatment (Maccat). All studies but one found a strong correlation between poor insight and incompetence.
conclusion The correlation between competence and insight in psychotic patients is strong. Psychotic patients with adequate insight tend to be competent, and psychotic patients with poor insight tend to be incompetent. In non-psychotic disorders there is no such overlap. Patients with non-psychotic disorders with adequate insight can be incompetent.