The effect of clinical outcome on platelet G proteins of major depressed patients

Platelet G protein subunits (G alpha i2, G alpha q and G beta) were measured in 15 non-treated depressed patients (recurrent major depression) and 15 age-and sex-matched healthy controls by using the Western immunoblot method. The depression severity was measured by the AMDP depression rating scale before start of treatment. The AMDP score ranged between 12 and 44. Patients were then treated with different antidepressant drugs (ATD) for 1 month, after which G protein and depression were reassessed. Results indicated that drug-free depressed patients displayed increased levels of G proteins subunits, in comparison to healthy controls. Antidepressant drug administration resulted in decrease of depression severity but only seven patients showed a net response to drugs (AMDP depression score less than 12), These drug-responding patients have also reduced G protein levels, while patients without significant improvement continued to display either the same levels of G proteins or higher, whatever the class of the drug administered. These results suggest that depression is associated to increase in G protein subunit levels and that the clinical outcome seemed to be the determining factor in further decrease occurring in G protein levels. (C) 1998 Elsevier Science B.V./ECNP.