Decrease of the D4 dopamine receptor messenger RNA expression in lymphocytes from patients with major depression.

Objectives: The evaluation of the possible role of dopamine in psychiatric disorders has been limited by the relative inadequacy of tools. A tempting approach to examine alterations of dopaminergic system in major depression is to examine the expression of dopamine receptors in peripheral blood mononuclear cells (PBMC).

Methods: D4 dopamine receptor (D4DR) messenger RNA (mRNA) expression in PBMC from 12 patients with major depressive disorder was examined before and after an 8-week treatment with paroxetine at 20-50 mg/day.