An automated analysis of REM sleep in primary depression.

The REM sleep of 23 nonpsychotic patients with primary depression was studied by means of an automated REM analyzer during a drug-free period and again during amitriptyline administration. Initial drug administration (50 mg) was associated with an immediate reduction in the number, average frequency, and average size of the rapid eye movements. The average REM size remained suppressed with continued drug administration while the average REM frequency showed a rebound which was responsible for a partial recovery of the number of REMs and total REM intensity to predrug levels. With regard to individual REM periods, REM frequency and REM intensity were redistributed during tricyclic administration so that the second REM period became more "intense" than the first REM period. This automated REM analysis technique provides an objective set of measures for characterizing discrete aspects of REM sleep during a depressive episode and for evaluating the changes in REM sleep during psychotropic trials.