Below is an instruction from Human. Write a response.
    ### Instruction:
    What is (are) Tourette syndrome ?
    ### Response:
    Tourette syndrome is a complex disorder characterized by repetitive, sudden, and involuntary movements or noises called tics. Tics usually appear in childhood, and their severity varies over time. In most cases, tics become milder and less frequent in late adolescence and adulthood.
    