Depression neurochemistry

Horton, RW (1992) The neurochemistry of depression evidence derived from studies of postmortem brain tissue. Molec. Aspects Med. 13 191-203. 

Acquas, Elio, and Gaetano Di Chiara. 1992. "Depression of Mesolimbic Dopamine Transmission and Sensitization to Morphine During Opiate Abstinence." Journal of Neurochemistry 58 1620-25. 

However, the exact problem in CNS amine neurotransmission remains a subject of much debate. One leading theory is that depression may be caused by an increased sensitivity of the presynaptic or postsynaptic receptors for these transmitters. That is, the neurochemistry of the brain has been changed in some way to make the amine receptors more sensitive to their respective amine neurotransmitters (norepinephrine, serotonin, and to a lesser extent, dopamine).21 This theory is based primarily on the finding that antidepressant drugs prolong the activity of amine neurotransmission in the brain, thereby causing a compensatory decrease in the sensitivity of the amine receptors.21,47... 

This volume of the Handbook of Neurochemistry deals with chemical mechanisms in the nervous systems of sick people. It is intentionally not a catalogue of neurochemical phenomena in specific diseases, as those entities are currently defined. Thus, there are no chapters on the Neurochemistry of Depression or Neurochemistry of Stroke. The choice to focus on mechanisms rather than on diseases deserves explication. 

In adcUdon to the biogenic amines, the amino acid neurotransmitters are also implicated in the neurochemistry of major depressive disorder. Neurotransmitter y-aminobutyric acid (GABA) levels are low in brain, cerebrospinal fluid, and blood of padents w ith major depressive disorder (Petty, 1995 Brambilla et al., 2003). 

The SSRIs were the first family of antidepressants not discovered by chance. Their development was planned according to what was known about the neurochemistry of depression, which partially explains their lack of side effects and efficacy of action. 

A more pressing issue surrounding SSRI use is when to stop treatment. While the therapeutic results last for some time after the end of SSRI treatment, most patients will relapse into a depressive state. Clinicians usually try to taper off the dose of SSRI in order to let the body get used to a different modulation of neurochemistry. Complete withdrawal is cautioned against since there have been reports of SSRI withdrawal effect. This effect is characterized by dizziness, fatigue, feelings of vagueness, and tension. 

---