AUTHOR=Smith Donald F., Jakobsen Steen 

TITLE=Molecular Neurobiology of Depression: PET Findings on the Elusive Correlation with Symptom Severity

JOURNAL=Frontiers in Psychiatry

VOLUME=Volume 4 - 2013

YEAR=2013

URL=https://www.frontiersin.org/journals/psychiatry/articles/10.3389/fpsyt.2013.00008

DOI=10.3389/fpsyt.2013.00008

ISSN=1664-0640

ABSTRACT=Molecular mechanisms in the brain are assumed to cause the symptoms and severity of
neuropsychiatric disorders. This review concerns the elusive nature of relationships between the
severity of depressive disorders and neuromolecular processes studied by positron emission
tomography (PET). The review provides a systematic account of all reports on PET and human
depressive disorders that have been listed in PubMed and published since March 2009, the time of
our last review on the topic. These recently published studies have concerned serotonergic,
dopaminergic, muscarinic, nicotinic, and GABAergic receptors, as well as central processes
dependent on monoamine oxidase, phosphodieasterase type 4, amyloid plaques, neurofibrillar
tangles, and P-glycoprotein. We find, however, that reliable causal links between neuromolecular
mechanisms and relief from depressive disorders have yet to be convincingly demonstrated. This
situation may contribute to the currently limited use of PET for exploring the neuropathways that
are currently viewed as being responsible for beneficial effects of antidepressant treatment regimes.