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Evidence for a biochemical lesion in depression
1Department of Pharmacology, National University of Ireland, Galway.
The Journal of Clinical Psychiatry
|April 25, 2000
Summary
Depression may stem from imbalances in brain chemicals like serotonin and norepinephrine. Antidepressant treatments appear to correct these monoamine system alterations.
Area of Science:
- Neuroscience
- Psychiatry
- Biochemistry
Background:
- The monoamine hypothesis suggests depression involves impaired central monoaminergic function.
- Deficiencies in norepinephrine and/or serotonin (5-HT) concentrations are implicated.
- Depletion studies correlate these deficiencies with depressive symptoms.
Purpose of the Study:
- To review evidence for lesions in serotonergic and noradrenergic systems in depression.
- To explore alterations in neurotransmitter concentrations, receptors, and postreceptor components.
- To examine the impact of antidepressant treatment on these systems.
Main Methods:
- Review of clinical and experimental studies on depression and monoamine systems.
- Analysis of cerebrospinal fluid, urine, and plasma neurotransmitter metabolite concentrations.
- Investigation of serotonin and norepinephrine receptor and transporter alterations.
- Examination of postreceptor, second messenger processes.
Main Results:
- Equivocal results regarding altered neurotransmitter metabolism.
- Evidence of reduced serotonin reuptake transporter activity and increased 5-HT2 receptor density.
- Consistent observation of beta-adrenoceptor up-regulation in the noradrenergic system.
- Evidence of cross-talk between noradrenergic and serotonergic systems.
Conclusions:
- Substantial evidence links lesions in serotonergic and noradrenergic systems to depression.
- Antidepressant treatment shows potential to reverse these observed alterations.
- Further research into postreceptor mechanisms and system interactions is warranted.