Frontiers in Psychiatry (Mar 2013)
Molecular neurobiology of depression: recent PET findings on the elusive correlation with symptom severity
Abstract
Molecular mechanisms in the brain are assumed to cause the symptoms and severity ofneuropsychiatric disorders. This review concerns the elusive nature of relationships between theseverity of depressive disorders and neuromolecular processes studied by positron emissiontomography (PET). The review provides a systematic account of all reports on PET and humandepressive disorders that have been listed in PubMed and published since March 2009, the time ofour last review on the topic. These recently published studies have concerned serotonergic,dopaminergic, muscarinic, nicotinic, and GABAergic receptors, as well as central processesdependent on monoamine oxidase, phosphodieasterase type 4, amyloid plaques, neurofibrillartangles, and P-glycoprotein. We find, however, that reliable causal links between neuromolecularmechanisms and relief from depressive disorders have yet to be convincingly demonstrated. Thissituation may contribute to the currently limited use of PET for exploring the neuropathways thatare currently viewed as being responsible for beneficial effects of antidepressant treatment regimes.
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