Midbrain binding of [123I]nor-beta-CIT in atypical depression.

Background: Altered serotonin (SERT) and dopamine transporter (DAT) densities have been recorded in major depression. Atypical depression (ATD) has been suggested to be connected to decreased serotonergic transmission, but no studies have been published on the association between brain serotonin transporter density and ATD.

Methods: PATIENTS with depression (n=29) were divided into three groups according to DSM-IV criteria: atypically depressed, melancholic patients, and "undifferentiated" patients. Depressive symptoms were evaluated with the 29-item Hamilton Depression Rating Scale (HAM-D-29). Single photon emission computed tomography (SPECT) with [(123)I]nor-beta-CIT was used to evaluate serotonin transporter density (SERT) in the midbrain and dopamine transporter density (DAT) in the striatum of patients and healthy controls (n=18).

Results: All subgroups except those with undifferentiated depression had lower SERT densities compared to controls. No significant differences were found in the densities between the subgroups. Atypical scores of HAM-D-29 were associated with SERT densities in the midbrain (beta=-0.40, t=-2.3, p=0.03), even after adjustment for age, gender and HAM-D-21 scores (beta=-0.39, t=-2.32, p=0.03).

Conclusions: The association between atypical scores of HAM-D-29 and midbrain SERT densities suggests a relationship between serotonergic dysfunction and ATD.