We studied the correlation between the efficacy of adepress (paroxerine) and the state of cell membranes assessed by the velocity of passive transmembrane ion transport in 39 patients (20 patients with chronic brain ischemia and 19 patients with ischemic stroke). Velocity of passive transmembrane ion transport estimated by the level of Na+-Li+ counter-transport (NLC) in the erythrocyte membrane was a criterion of the cell membrane functional activity. The higher the NLC velocity, the more severe was the course of depression with the development of cognitive dysfunction and pain syndromes in patients with chronic brain ischemia and stroke. At the same time, the higher clinical efficacy of adepress (paroxerine) was seen in patients with higher NLC velocities. Estimation of NLC velocity in the erythrocyte membrane may be used for identification of risk groups for the development of affective disorders in patients with stroke and chronic brain ischemia as well as for prediction of treatment efficacy.