Dopamine is a neurotransmitter that is classified as a catecholamine. A catecholamine is a specific type of molecule that relays messages throughout the brain. Dopamine is a precursor to adrenaline and is involved in neurological processes that control movement and responses to stimuli, such as pain and temperature sensations. Taurine is an organic acid which is also involved in neurotransmission and is believed to be an antioxidant. Abnormally high levels of dopamine or taurine can lead to a variety of health complications.
Tourette's syndrome is characterized by involuntary movements known as tics. These movements can be caused by an excess of dopamine molecules in the brain. An area of the brain known as the basal ganglia is involved in the production of smooth, controlled movements. According to a 2003 study conducted by A Díaz-Anzaldúa, et al., and published in "Molecular Psychiatry," too much dopamine input to the basal ganglia can result in abnormal motor activity. Excess dopamine can also produce violent, impulsive behavior.
Schizophrenia is a mental condition characterized by abnormal thought patterns. This condition causes patients to have delusions, hear voices or experience paranoia. It is believed that dopamine may play a role in the development of schizophrenia. As explained by K. L. Davis and colleagues in the April 2001 issue of "The American Journal of Psychiatry," excess dopamine can affect certain brain regions, allowing the symptoms of schizophrenia to emerge. It is important to note that schizophrenia manifests itself differently in individual patients and excess dopamine may not be the cause of schizophrenia in every patient that has this mental condition.
In the July 1986 edition of "The Annual Review of Biochemistry," C. E. Wright and colleagues explain that taurine is involved in many physiological processes, although the details of these processes are not completely known. Thus, it is difficult to determine the effects of excess taurine on the different systems of the body. The kidneys are responsible for removing excess taurine from the the body. Consistently high taurine levels may cause damage to the kidneys over time. It is speculated that excess taurine can cause seizures in rare cases. This would indicate that taurine is able to stimulate the hypothalamus, a brain region that is often overstimulated during seizure activity.