The National Center for Health Statistics reports that more than 1 in 20 Americans over the age of 12 suffered from depression in 2006. Interestingly, a 2005 review in "The New England Journal of Medicine" suggests that the majority of these individuals do not receive even minimal care for their condition. This is unfortunate, for mental health experts now have a variety of treatment modalities at their disposal, including medications that alter the levels of neurotransmitters, including dopamine.
Neurotransmitters in Depression
Neurotransmitters, such as serotonin and dopamine, are chemical messengers that permit the movement of electrical impulses through your brain and nervous system. The concentration of these chemicals in the small gaps, or synapses, between adjacent nerves determines the strength and frequency of impulse transmission. According to a 2002 review in the journal "Thérapie," neurotransmitter deficits play a major role in the development of depression, and antidepressant drugs exert their effects by modifying the levels of neurotransmitters in your brain.
Dopamine Exerts Wide-Ranging Effects
Dopamine is a monoamine neurotransmitter that is related to epinephrine, or adrenalin. Dopamine is produced in your central nervous system by the enzymatic conversion of the amino acid L-tyrosine to L-dopa and then to dopamine. Dopamine exerts its effects in your brain by stimulating an array of dopamine-sensitive receptors in various locations. Alteration of dopamine concentrations in brain centers that control mood, emotion and motivation is believed to contribute to depression.
Dopamine Drugs
Some people with mild depression opt to avoid prescription drugs and take dietary supplements, such as L-tyrosine or St. John's wort, instead. L-tyrosine ostensibly increases the production of dopamine in your brain. According to a 2003 "CNS Drugs" review, St. John's wort inhibits the breakdown and reabsorption of dopamine in the synapses. Neither of these remedies has been approved in the United States for treating depression. The most commonly used prescription drugs that primarily affect brain dopamine levels are the monoamine oxidase inhibitors, or MAOIs, such as selegiline, toloxatone, phenelzine, tranylcypromine and moclobemide.
Considerations and Precautions
Depression is a serious condition that usually involves both environmental and biochemical factors. Furthermore, due to the complex interplay among different neurotransmitters in the human brain, multiple biochemical pathways may be involved in any one person's depression. Newer antidepressant medications, such as serotonin-norepinephrine reuptake inhibitors, are designed to address this issue. MAOIs are notorious for interacting with other drugs, foods and herbal supplements, and they are usually not the first choice of physicians for treating depression. If you think you are suffering from depression, talk with your doctor about your options.
References
- NCHS Data Brief: Depression in the United States Household Population, 2005--2006; L.A. Pratt, D.J. Brody; September 2008
- "The New England Journal of Medicine"; Prevalence and Treatment of Mental Disorders, 1990 to 2003; R.C. Kessler, et al.; June 2005
- "Thérapie"; Mechanism of Action of Antidepressant Drugs and Therapeutic Perspectives; M. Bourin, et al.; July-August 2002
- "CNS Drugs"; Mechanism of Action of St. John's Wort in Depression: What Is Known?; V. Butterweck; 2003
