Dopamine is a neurotransmitter, or a chemical that helps brain cells communicate with one another. Its specific function is to regulate attention, memory, pleasure, reward and motor functions. Dopamine levels that are too low can lead to mental health symptoms in adolescents, including difficulty concentrating or depression. When dopamine levels are too high, they can cause psychosis. In addition, dopamine is known to play a central role in addiction.
Attention-Deficit Hyperactivity Disorder
Attention-deficit hyperactivity disorder, or ADHD, is usually diagnosed in childhood but can continue into the teen years. Teens with ADHD have difficulty concentrating and sitting still. Scientists believe ADHD is caused in part by a low level of dopamine. Therefore, treatment for the disorder often includes medications such as Ritalin, which, according to researchers at the Brookhaven National Laboratory in Upton, New York, increases the the level of dopamine in the brain.
Depression
In addition to ADHD, low levels of dopamine are associated with depression in teens. In response, along with therapy, teens are sometimes treated with a drug known as a norepinephrine and dopamine reuptake inhibitor, or NDRI. NDRIs increase the levels of both norepinephrine and dopamine in the recipient by reducing the ability of cells to absorb these neurotransmitters. The only NDRI approved by the Food and Drug Administration for the treatment of depression as of September 2010 is bupropion, which goes by the brand name Wellbutrin. A form of bupropion with the brand name Zyban is also available as a smoking cessation drug.
Schizophrenia
Schizophrenia is a mental health disorder characterized by psychosis, a loss of touch with reality. The age of onset for the disorder is often late teens for boys, although it typically emerges later in women. The psychotic symptoms of schizophrenia, as well as other psychotic disorders, are believed to be the result of an overabundance of dopamine in the brain. To treat these symptoms, psychiatrists prescribe antipsychotic medications that reduce dopamine levels.
Drug-Induced Psychosis
Because they raise dopamine levels in the brain, several drugs prone to abuse, including amphetamines, methamphetamine and cocaine, can produce psychotic symptoms similar to those experienced by people with schizophrenia. The dopamine-altering affects of methamphetamine are especially pronounced, according to the National Institute on Drug Abuse, often resulting in long-term brain damage. "Psychotic symptoms can sometimes last for months or years after methamphetamine abuse has ceased," NIDA reports.
Addiction
Because dopamine is responsible for the brain's processing of pleasure and reward, it is believed to be largely responsible for the development of addictive behaviors. For example, when a teen experiences pleasure as a result of ingesting a drug such as methamphetamine, he is motivated to repeat the experience, thus initiating a self-perpetuating cycle of addiction. As explained by NIDA, drug abuse leads to "initial pleasurable feelings, and [a] subsequent dependence and addiction, resulting from disruption of the dopamine neurotransmitter system."
References
- National Institute on Drug Abuse: Impacts of Drugs on Neurotransmission
- "The Journal of Neuroscience"; Therapeutic Doses of Oral Methylphenidate Significantly Increase Extracellular Dopamine; Nora D. Volkow, et al.; 2001
- MayoClinic.com: Norepinephrine and Dopamine Reuptake Inhibitors (NDRIs)
- National Institute of Mental Health: Schizophrenia-Related Gene Linked to Imbalance in Dopamine Pathways
- National Institute on Drug Abuse: Research Report Series: Methamphetamine Abuse and Addiction
