The studies established some differences in the serotonin metabolism in psychopaths and in patients with sluggish schizophrenia (261+/-9 ng/ml and 329+/-7 ng/ml of whole blood respectively). A comparison of the homovanilin acid content in the blood serum of patients in both groups (normals -62.1+/-9.3 ng/ml, psychopathic personalities -86.0+/-10.1 ng/ml, schizophrenic patients -34.5+/-8.6 ng/ml) points to a tendency towards an intensification of the dopamine metabolism in patients with psychopathy and a drop in the intensity of dopamine metabolism in schizophrenic patients.