Visually-evoked event-related potentials and oral citalopram challenge test

The P3 latency of the visually.evoked ERP in the migraine attack is inversely correlated with the platelet serotonin content, a measure that reflects central serotonergic transmission [2]. Citalopram i.v. leads to dose-related increase in plasma cortisol level in healthy subjects, but not in depressed patients, probably due to serotonergic hypofunction in depression [1, 3]. 19 inpatients with major depression were treated with citalopram. Before treatment, visually-evoked ERP were investigated. Monoaminergic function was determined by oral citalopram challenge test. We detected a significant inverse correlation between serotonergic hypofunction before treatment as measured by the cortisol response and the P3 latency (r=-0.739, p=0.001). These results suggest that, in depressed patients, the P3 latency might depend on the serotonergic system. In order to prove that visually-evoked ERP and cortisol responsiveness to citalopram challenge is a true indicator of monoaminergic function, further studies involving larger samples are required.

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2. Evers S, Quibeldey F et al. Dynamic changes of cognitive habituation and serotonin metabolism during the migraine interval. Cephalalgia 1999; 19: 485–491

3. Kapitany T, Schindl M et al. The citalopram challenge test in patients with major depression and in healthy controls. Psychiatry Res. 1999; 88: 75–88