Mental capacity to consent to treatment and the association with outcome: a longitudinal study in patients with anorexia nervosa

BACKGROUND: Relevance of diminished mental capacity in anorexia nervosa (AN) to course of disorder is unknown.

AIMS: To examine prognostic relevance of diminished mental capacity in AN.

METHOD: A longitudinal study was conducted in 70 adult female patients with severe AN. At baseline, mental capacity was assessed by psychiatrists, and clinical and neuropsychological data (decision-making) were collected. After 1 and 2 years, clinical and neuropsychological assessments were repeated, and remission and admission rates were calculated.

RESULTS: People with AN with diminished mental capacity had a less favourable outcome with regard to remission and were admitted more frequently. Their appreciation of illness remained hampered. Decision-making did not improve, in contrast to people with full mental capacity.

CONCLUSIONS: People with AN with diminished mental capacity seem to do less well in treatment and display decision-making deficiencies that do not ameliorate with weight improvement.