<prompt> All are habit disorder exceptNail bitingThumb suckingTemper tantrumTics  <response>: 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 TDs, 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 