• brief, patterned, rapid, repetitive, purposeless, semivoluntary or involuntary contractions of the same muscle or group of muscles
• usually in children
• eg nervous tic of corner of mouth, winking
• may take form of sniffing, grunting, snorting, pouting social issues
• may be able to suppress it with concentration for a short time
• no consistent psychopathology has been identified
• Gilles de la Tourette syndrome – severe form – tic movements and swearing.