problems with concentrating, and withdrawal  from social activities may predominate.
restless legs syndrome An urge to move the legs, usually accompanied or caused by
uncomfortable and unpleasant sensations in the legs (for pediatric restless legs syn-
drome, the description of these symptoms should be in the child’s own words). The
symptoms begin or worsen during periods of  rest or inactivity. Symptoms are partially
or totally relieved by movement. Symptoms are worse in the evening or at night than
during the day or occur only in the night/evening.
restricted affectivity Little reaction to emotionally arousing situations; constricted
emotional experience and expression; indiffer ence and aloofness in normatively engaging
situations. Restricted affectivity is a facet of the broad personality trait domain D ETACH -
MENT .
rigid perfectionism Rigid insistence on everything being flawless, perfect, and without
errors or faults, including one’s own and ot hers’ performance; sacrificing of timeliness
to ensure correctness in every detail; believi ng that there is only one right way to do
things; difficulty changing ideas and/or viewpoint; preo ccupation with details, orga-
nization, and order. Lack of rigid perfection ism is a facet of the broad personality trait
domain D ISINHIBITION .
risk taking Engagement in dangerous, risky, and po tentially self-damaging activities, un-
necessarily and without regard to consequences; lack of concern for one’s limitations and
denial of the reality of  personal danger; reck less pursuit of goals regardless of the level of
risk involved. Risk taking is a facet of the broad personality trait domain D ISINHIBITION .
rumination (rumination disorders) Repeated regurgitation of food over a period of at