Lower brain blood flow is associated with depression, according to a new study published in the August issue of the Society of Nuclear Medicine.

Using single photon emission computed tomography (SPECT)--a molecular imaging/nuclear medicine procedure in which injected radiotracers are used to produce three-dimensional, computer-reconstructed images that give information about structure and function--the investigators confirmed previously published findings that brain blood flow in depressed patients is lower than in healthy controls, especially in frontal, limbic and subcortical brain regions.

The researchers additionally found that treatment with an antidepressant normalized blood flow, while treatment with electroconvulsive therapy (ECT) was associated with further decreases in blood flow. Patients whose depression did not improve did not experience any changes in blood flow.

The authors note that while psychiatry currently involves the clinician making subjective judgments about how to proceed with treatment, these results imply that brain imaging could give objective support to the decision-making process.