The mouse who couldn't stop washing: pathologic grooming in animals and humans.

The basic science literature is replete with descriptions of naturally occurring or experimentally induced pathological grooming behaviors in animals, which are widely considered animal models of obsessive-compulsive disorder (OCD). These animal models rely largely on observed similarities between animal behaviors and human OCD behaviors, and on studies of animal pathological grooming disorders that respond to serotonin enhancing drugs. However, current limitations in assessment of complex cognition and affect in animals precludes the field's ability to match the driving primary processes behind observable phenomenology in animal "OCD" with human behavioral disorders. We propose that excessive grooming behaviors in animals may eventually prove to be equally, or possibly more relevant to, other conditions in humans that involve pathological grooming or grooming-like behaviors, such as trichotillomania, body dysmorphic disorder, olfactory reference syndrome, compulsive skin-picking, and onychophagia. Research is needed to better understand pathological grooming behaviors in both humans and animals, as animal models have the potential to elucidate pathogenic mechanisms and inform the treatment of these psychiatric conditions in humans.