A number of anorexic young women develop bulimia, a condition in which binge eating is driven so intensely they cannot resist it. Although this drive has the character of a compulsion the patients do not as a rule suffer from obsessional-compulsive neurosis. A questionnaire was developed and used to determine whether similar compulsive drives manifest themselves in restricting anorexics and whether there are compulsive features resembling patients with compulsive personality disorder (as described in DSM-III) in eating disorders. A total of 162 patients were studied, comprising 42 controls, 30 depressed patients, 34 non-bingeing anorexics, 28 bingeing anorexics and 28 compulsive patients. The questionnaire was shown to be a stable instrument and, on the compulsion scale, the anorexics, bulimics and compulsive patients all scored very highly (mean +/- S.E.; 32.1 +/- 1.9, 35.8 +/- 1.9, 28.0 +/- 2.2, respectively) compared to the controls (13.1 +/- 1.1, p < 0.005). The compulsive patients did not have anorexia-type eating disorders. It was concluded that many of the factors which underlie compulsive personality disorder are present in primary eating disorders and the compulsive nature of anorexia could not be ignored when treatment was considered. The difference between compulsive behaviour and addiction is discussed in the light of the failure of long-term naloxone infusion to cure severe anorexia, even though some patients had dramatic weight gains associated with the antilipolytic action of naloxone.