Antidepressants and periodic leg movements of sleep.

BACKGROUND: Frequent electroencephalographic arousals or awakenings associated with periodic leg movements (PLM) might be responsible in part for the complaints of sleep disturbances made by patients treated with antidepressants. Past studies, however, have determined the effects of only certain limited antidepressants, generally in small numbers of subjects, and never in a head-to-head study. METHODS: A total of 274 consecutive patients taking antidepressants and 69 control subjects not taking antidepressants met criteria among patients referred for overnight diagnostic polysomnography. Periodic leg movements were visually counted and the PLM index (PLMI) was calculated. RESULTS: The venlafaxine and selective serotonin reuptake inhibitor (SSRI) groups had significantly higher mean PLMIs than control and bupropion groups. Periodic leg movement indexes at thresholds considered to be of potential clinical significance were more statistically prevalent in the SSRI and venlafaxine groups compared with the control and bupropion groups. The odds ratio of having a PLMI greater than 20 was 5.15 for the SSRI group and 5.24 for the venlafaxine group compared with the control group. CONCLUSIONS: Venlafaxine and SSRI-induced PLM are likely to be the result of enhanced serotonergic availability and secondarily decreased dopaminergic effects. The results of this study might assist in the selection of antidepressants, especially in patients with pronounced sleep complaints.