All are habit disorder except

* Definition: * Habit disorder is a term used to describe several related disorders linked by the presence of repetitive and relatively stable behaviour that seem to occur beyond the awareness of the person performing the behaviour. * The first group of habit disorder includes "Tic Disorder" * Tics are involuntary movements, sounds, or words that are sudden, rapid, recurrent and nonrhythmic" * In addition to TD's, body-focussed behaviours, * Recurrent hair pulling - Trichotillomania (TTM) * Skin picking (SP) * Nail biting , are included within habit disorders. * Head banging, rocking of body, teeth grinding & thumb sucking are repetitive disorders. * Seen in children between age group of 6 months to 2 years. * Benign & self-limited. * The movements serve a means of tension discharging in children. * As children become older, they learn to inhibit some of their rhythmic patterns. * REF : DAVIDSONS 10TH ED