Under the term Tics, we group together involuntary vocal or other motor behaviours. There are simple Tics such as blinking, throat scraping and sniffing, and complex Tics such as repeating someone's gestures (echopraxia) or obscene gestures (copropraxia). Coprolalia is characterised by the repetition of nonsense, taboo or reprehensible words. We speak of Tourette's Syndrome, when vocal and motor tics are present, often starting in childhood. Tics can appear and disappear spontaneously, sometimes being increased by stress.