The brain adapts to psychotropic drugs by increasing or decreasing neurotransmitter production and receptor density
In 1996, neuroscientist, provost of Harvard University, and the director of NIMH through 1996-2001 Steve Hyman published a paper in the American Journal of Psychiatry titled “Initiation and Adaptation: A Paradigm for Understanding Psychotropic Drug Action” which told of how all psychotropic drugs could be understood to act on the brain.
Antipsychotics, antidepressants, and other psychotropic drugs “create perturbations in neurotransmitter functions.” In response, the brain goes through a series of compensatory adaptations. Drugs that block a neurotransmitter (antagonists), such as antipsychotics, make the autoreceptors tell the presynaptic neurons spring into hyper gear and release more of it, and the postsynaptic neurons increase the density of their receptors for that chemical messenger. Drugs that increase the synaptic levels of a neurotransmitter (agonist) (as an antidepressant does), the presynaptic neurons decrease their firing rates and the postsynaptic neurons decrease the density of their receptors for the neurotransmitter. In each instance, the brain is trying to nullify the drug’s effects. “These adaptations,” Hyman explain “are rooted in homeostatic mechanisms that exist, presumably, to permit cells to maintain their equilibrium in the face of alterations in the environment or changes in the internal milieu.”
However, after a period of time, these compensatory mechanisms break down. The “chronic administration” of the drug the causes “substantial and long-lasting alterations in neural function.” As part of this long-term adaptation process, there are changes in intracellular signaling pathways and gene expression. After a few weeks the person’s brain is functioning in a manner that is “qualitatively different from the normal state.” Modern medicine tends to target the pathology of an illness rather than preventing it. This may also involve right hemisphere deficit because the right hemisphere is responsible for the ability to put ourselves in anothers shoes.
References
- Whitaker, Robert. (2010). Anatomy of an Epidemic Magic Bullets, Psychiatric Drugs, and the Astonishing Rise of Mental Illness in America 5. The Hunt for Chemical Imbalances (EPub p. 115). Crown Publishing: New York , NY.
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Type:🔴 Tags: Biology / Neuroscience / Biochemistry / Neurochemistry / Pharmacology Status:☀️