<unk>  have not been fully elucidated.<unk>  syndrome (abbreviated as<unk> 's or TS) is an inherited neurodevelopmental disorder that begins in childhood or adolescence, characterized by the presence of multiple motor tics and at least one phonic tic, which characteristically wax and wane.<unk> 's syndrome occurs along a spectrum of tic disorders, which includes transient tics and chronic tics. The exact<unk> of<unk> 's is unknown, but it is well established that both genetic and environmental factors are involved. The overwhelming majority of<unk>  of<unk> 's are inherited, although the exact mode of inheritance is not yet known, and no gene has been identified. Tics are believed to result from dysfunction in the thalamus, basal ganglia, and frontal cortex of the brain, involving abnormal activity of the brain chemical, or neurotransmitter, dopamine. In addition to dopamine, multiple neurotransmitters, like serotonin, GABA, glutamate, and histamine (H3-receptor), are involved. Non-genetic factors—while not causing<unk> 's—can influence the severity of the disorder. Some forms of<unk> 's may be genetically linked to obsessive-compulsive disorder (OCD), while the relationship between<unk> 's and attention-deficit hyperactivity disorder (ADHD) is not yet fully understood.
Causes and origins of Tourette syndrome
Societal and cultural aspects of Tourette syndrome
Risk factors of schizophrenia
Hallucinogen persisting perception disorder
Eating disorders and memory
Attention deficit hyperactivity disorder controversies
Global perceptions of autism
Cause of obsessive-compulsive disorder