Correlations for serotonin levels and measures of mood in a nonclinical sample.

The Beck Depression Inventory is frequently used to detect depression and its severity because depression is a prevalent mood disorder and is commonly treated by prescription of selective serotonin-reuptake inhibitors such as Prozac. The importance of serotonin (5-HT) in the treatment of major depression is evident but the nature of this involvement is unclear. In this study, the characteristics of platelets are employed as a peripheral model of the neuron to estimate central serotonergic activity, which is a consequence of numerous factors including 5-HT2 receptor sensitivity. The greater the sensitivity of the platelet serotonin receptors, the lower the concentration of serotonin required to mobilise a particular amount of calcium from internal stores through serotonin stimulation. Hence, Platelet 5-HT2 receptor sensitivity is inferred from the concentration of serotonin that is required to produce half maximal intracellular calcium mobilisation (EC50). In the present study, the correlation of -.422 between scores on the Beck Depression Inventory and EC50 in a sample of 49 university students was significant, implying that mood is significantly related to 5-HT2 receptor sensitivity, such that increases in depressed mood are accompanied by increases in 5-HT2 receptor sensitivity.