Effect of two antidepressant drugs on REM sleep and EMG activity during sleep

In a placebo-controlled study, the effects on sleep of single and repeated doses of imipramine and dexnafenodone, an antidepressant drug under develop ment, were investigated in young, healthy volunteers. In contrast to placeb o, both drugs suppressed REM sleep substantially after acute and repeated a dministration. As a consequence, REM sleep latencies increased under active treatment to mean values which were about two to four times larger than ba seline values. Since the active inhibition of the muscle tone is a distinct feature of REM sleep, we studied the influence of the two antidepressant d rugs on this variable. By means of computerised EMG analysis, tonic and tra nsient EMG activity were computed for total recording time and for the diff erent sleep stages. While tonic EMG activity during sleep was increased wit h both drugs, transient EMG events remained unaffected. Computerised analys is of the microstructure of sleep is an effective tool for studying the eff ect of antidepressant drugs on sleep.