Pica and the obsessive-compulsive spectrum disorders

Background. The concept of a spectrum of obsessive-compulsive related disorders may have clinical and research heuristic value in the approach to disorders similar to obsessive-compulsive disorder (OCD) in respect of phenomenology and psychobiology. Like other repetitive and ritualistic behaviours, pica may be postulated to fall at times on this spectrum. Methods. Five cases of pica seen at our clinics are presented here in order to test this hypothesis. Phenomenology, neurobiology (where available) and pharmacotherapy data are provided in order to consider a possible relationship with OCD and OCD spectrum disorders. Results. In 2 of the cases, pica appeared to be a compulsion and patients had additional symptoms which met diagnostic criteria for OCD. In 2 of the cases, the clinical picture and neurobiological data were reminiscent of an impulse control disorder. Four of the 5 patients responded to treatment with a serotonin re-uptake inhibitor (SRI). Conclusion. These results are consistent with a hypothesis that at least some cases of pica may usefully be conceptualised as lying within a compulsive-impulsive spectrum of symptoms and disorders.