Restrictive eating in anorexia nervosa often comes with rigidity, all-or-nothing thinking, and difficulty shifting approach. Those same features sit at the centre of obsessive-compulsive personality disorder, which raises a reasonable question about how far the two overlap.
Touzeau and colleagues measured obsessive-compulsive personality traits in 208 hospitalised adults and adolescents with anorexia nervosa and 124 healthy peers, using a scale covering rigidity, emotional overcontrol, maladaptive perfectionism, reluctance to delegate, and difficulty with change. Patients were assessed before and after weight restoration treatment.
Scores were significantly higher in the anorexia group across all five areas, though still lower than in people who actually have the personality disorder. Within the anorexia group, higher scores went with greater eating disorder severity.
Two findings complicate the picture. The traits did not shift with weight restoration, and they were not associated with treatment outcome. The authors conclude these traits may deserve attention in treatment while suggesting that co-occurring obsessive-compulsive personality disorder may not be what drives the rigidity that keeps anorexia going.
If rigid rules around eating or perfectionism are affecting your life, or your child's, support is available.
The overlap being examined
Anorexia nervosa frequently presents with cognitive inflexibility, meaning difficulty shifting from one approach or rule to another, along with dichotomous thinking, where options are seen as all or nothing with no middle ground. Rigidity of this sort is also central to obsessive-compulsive personality disorder, known in the ICD as anankastic personality disorder, a persistent pattern of perfectionism, control and inflexibility.
The overlap has led to a reasonable hypothesis: that obsessive-compulsive personality traits are part of what maintains restrictive eating, and that treating them might loosen the illness. This study tested whether those traits track illness severity and whether they predict how someone responds to treatment.
What the study did
Obsessive-compulsive personality traits were measured with the Pathological Obsessive Compulsive Personality Scale, which yields a total score and covers five domains: Rigidity, Emotional Overcontrol, Maladaptive Perfectionism, Reluctance to Delegate, and Difficulty with Change.
Three comparisons were made. Hospitalised adults and adolescents with anorexia nervosa were compared with healthy peers. Within the patient group, trait scores were tested against other indices of clinical severity. And patients were assessed before and after weight restoration treatment, so that any change in these traits with renourishment could be observed directly. That last design feature is the valuable one, because it can distinguish a stable personality trait from something that merely looks like one while a person is starved.
What it found
Scores were significantly higher among the 208 patients with anorexia nervosa than the 124 healthy peers, with a total of 173.2 against 132.3, a difference unlikely to have arisen by chance. The elevation held across all five domains rather than being driven by one.
Within the anorexia group, higher trait scores were associated with higher scores on two eating disorder measures, the EDE-Q and the YBC-EDS, with correlations of 0.29 and 0.28. Correlations of this size are modest. They indicate a real association in which these traits and illness severity move together somewhat, while leaving most of the variation between patients unexplained.
The two negative findings carry as much weight. Trait scores did not change with weight restoration, and they were not significantly associated with treatment outcome. The authors also note that although scores were elevated compared with healthy peers, they were lower than in populations who have obsessive-compulsive personality disorder itself.
What the authors conclude, and what they do not
The conclusion is carefully bounded. These traits are elevated in anorexia nervosa and relate to how severe the illness is, but they did not predict who got better. The authors suggest the traits may merit attention in treatment, while proposing that co-occurring obsessive-compulsive personality disorder may not be central to the kind of rigidity that perpetuates the illness.
Two limits are worth stating. The correlations reported are associations measured at one point in time and cannot establish that the traits cause greater severity, or the reverse. And the study followed short-term outcome after weight restoration in a hospital setting, so it leaves open whether these traits matter over a longer course or for relapse.
If rigid rules around food, perfectionism, or a need for control are affecting you or someone you care about, a psychologist can help you work through it.