“A sta­tis­tical stu­dy of hal­luci­na­tions in 1009 cases of manic­depres­si­ve psyc­ho­ses with 1408 cases of schizoph­re­nia and 496 cases of gene­ral pare­sis as cont­rols leads to the fol­lowing conclusions: Hal­luci­na­tions are absent in 70 per cent of the males and 63 per cent of the fema­les in the manic-depres­si­ve group as com­pa­red with 25 per cent of the males and 19 per cent of the fema­les in schizoph­re­nia, and 73 per cent of the males and 58 per cent of the fema­les in gene­ral pare­sis. […] The­re is con­si­de­rable associa­tion between delusions and hal­luci­na­tions; in all three groups the­re is a posi­ti­ve associa­tion between no delusions and no hal­luci­na­tions[.]” #

Karl M. Bow­man, Alice F. Ray­mond: “A Sta­tis­tical Stu­dy of Hal­luci­na­tions in The Manic-Depres­si­ve Psyc­ho­ses” #