Similarity of non-REM abnormalities in schizophrenia and depression.

Abstract

<h3>To the Editor.—</h3> Hiatt and co-Workers¹have described an abnormal distribution of sleep spindles in five actively ill, unmedicated, schizophrenic patients. Sleep spindles are bursts of sinusoidal, 12- to 15-Hz waves that, along with delta waves, are electroencephalographic (EEG) hallmarks of non— rapid eye movement (NREM) sleep. In normal young adults, the density (bursts per minute) of spindles shows a linear increase across the successive NREM periods (NREMPs) of sleep (M.G., I.F., G. Fein, T.C.F., C.M., unpublished data, 1984) (Figure). This pattern is the mirror image of that observed for delta waves, whose abundance and amplitude decline across NREMPs.² In schizophrenic patients, Hiatt et al1 found an abnormally high-spindle density in the first NREMP associated with an abnormally low level of delta waves; spindle density in NREMPs 2 through 4 did not differ from that of normal subjects (Figure). The NREMP 1 in the schizophrenic patients was also