P1vital CNS Experimental Medicine : EMOTIONAL TEST BATTERY

morphed facial expressions developed by Young et al READ MORE:

Although it is well established that antidepressants that increase serotonin or noradrenaline in the brain are effective in treating depression, there is no neuropsychological account of how these changes relieve depressive states.

Researchers in Oxford led by Prof Guy Goodwin have shown that seven days administration of the SSRI citalopram (20 mg, PO) effects emotional processing in a selective manner that may be relevant to its mechanism of action. Subjects completed a facial expression recognition task following citalopram or placebo (between-subjects design, double-blind). Facial expressions associated with five basic emotions: happiness, sadness, fearfulness, anger and disgust were displayed. Each face had been 'morphed' between neutral (0%) and each emotional standard (100%) in 10% steps, leading to a range of emotional intensities. Volunteers receiving citalopram gave lower intensity ratings to facial expressions of fear, relative to the rating given by those receiving placebo. Citalopram did not affect ratings of ‘happy’ per se but it did induce a ‘happy’ bias that is volunteers falsely labeled negative facial expressions as happy. Notable differences in overt mood were also not apparent in these volunteers. When citalopram (10 mg IV) was infused acutely it increased the detection of fear and happy faces. These results suggest that short-term administration of antidepressant drugs may affect neural processes involved in the processing of social information.

These effects may represent an early action of SSRIs on social and emotional processing that is relevant to their therapeutic mechanism. The advantage of this model is that putative antidepressants can potentially be assessed in normal volunteers in a relatively short period of time.