of psychiatric research has placed an emphasis on proximate mechanisms as the cause for illness. in contrast, evolutionary theory has engendered questions regarding how distal mechanisms may be implicated with pathogenesis. ocd involves several behavioral schemata that may have been preserved over evolutionary history. numerous species have inherited cognitive patterns that lend to checking for danger, avoiding contamination, and hoarding food. theorists have hypothesized that a dysfunction in any of these strategies could lead to the expression of ocd. this conjecture is further supported by evidence that such inherited, species-specific strategies are stored in the basal ganglia. lick granuloma from excessive licking when considering the expression of ocd in non-human species, researchers have studied acral lick dermatitis (also known as lick granuloma) in large canines. this disorder is characterized by excessive licking or scratching that leads to alopecia (hair loss) and subsequent granulomatous lesions (vascular tissue on the surface of a wound). rapoport et al. found that this obsessive-compulsive behavior was alleviated in canines after administering clomipramine. thus, it is conceivable that evolutionary selected traits could become maladaptive proceeding neurological dysfunction.