Other obsessive-compulsive and related disorders. In body dysmorphic disorder, the
obsessions and compulsions are limited to concerns about physical appearance; and in
trichotillomania (hair-pulling diso rder), the compulsive behavior is limited to hair pulling
in the absence of obsessions. Hoarding diso rder symptoms focus exclusively on the per-
sistent difficulty discarding or parting with  possessions, marked distress associated with
discarding items, and excessive accumulation of  objects. However, if an individual has ob-
sessions that are typical of OCD (e.g., concer ns about incompleteness or harm), and these
obsessions lead to compulsive hoarding behaviors (e.g., acquirin g all objects in a set to at-
tain a sense of completeness or not discarding old newspape rs because they may contain
information that could prevent harm), a di agnosis of OCD should be given instead. 
Eating disorders. OCD can be distinguished from anorexia nervosa in that in OCD the
obsessions and compulsions are not limite d to concerns about weight and food.
Tics (in tic disorder) and stereotyped movements. A tic is a sudden, rapid, recurrent,
nonrhythmic motor movement or vocalization (e.g., eye blinking, th roat clearing). A ste-
reotyped movement  is a repetitive, seemingly driven, nonfunctional motor behavior (e.g.,
head banging, body rocking,  self-biting). Tics and ster eotyped movements are typically
less complex than compulsions and are not aimed at neutralizing obsessions. However,
distinguishing between complex tics and comp ulsions can be difficult. Whereas compul-
sions are usually preceded by obsessions, tics  are often preceded by premonitory sensory