DURING the past few years several investigators1-5 have reported on the presence of atypical circulating lymphocytes in schizophrenic patients; some of them2-4 have suggested that the atypical cells seen may be manifestations of a hypothetical genetically transmitted biological defect in schizophrenia. One of the present authors (B.B.) had been recording normal blood pictures on schizophrenic patients at the New York State Psychiatric Institute until 1957, and thereafter also began to record an increasing number of atypical lymphocytes. These data seem, in retrospect, to coincide with the time that phenothiazine drugs came into general use in this hospital.
The purposes of this paper are (1) to report the results of a controlled study undertaken to determine the effect of phenothiazines on the frequency of occurrence of atypical lymphocytes as seen in increasing numbers after 1957 in our laboratory; and (2) to compare them with those described by other investigators.