Diffuse electroencephalogram slowing in psychiatric patients: a preliminary report.

Diffuse slowing constitutes 40% of all electroencephalogram (EEG) abnormalities in psychiatric patients. Correlations have been demonstrated between the degree of slowing of the EEG and impairment of functions such as awareness, attention, memory, and comprehension. We conducted the current study in order to determine whether diffuse EEG slowing in hospitalized psychiatric patients correlated with hospitalization indices. Twenty-five patients with diffusely slow EEGs were selected for the study, and 25 patients with normal EEGs were matched to these subjects. Medical records were reviewed for each patient's diagnosis, length of stay, number of medications, and the dosages. Length of stay was significantly longer in the slow EEG group. The number of psychotropic medications used and the dosages of antipsychotic medications were also significantly higher in the slow EEG group. We concluded that the longer length of stay and the increased number of medications and dosages in the slow EEG group may be a reflection of increased illness severity.