Personality and Reactivity to Stimulants and Depressants

Thirty-one nonpatient male volunteers with four distinct Minnesota Multiphasic Personality Inventory (MMPI) patterns (neurotic triad pattern, psychotic tetrad pattern, elevated mania (Ma) and psychopathic deviant (Pd) scales, and normal pattern) were selected in order to investigate the differential effect of stimulants and depressants on differential personality types. Two stimulants, caffeine sodium benzoate and methylphenidate hydrochloride, and two depressants, secobarbital sodium and amobarbital sodium, were given to various combinations of the four types of subjects in groups of 7 to 10 men. The subjects' scores on two cognitive tests and one motor test following drug administration were compared. Several significant intergroup differences are reported. The group with the psychotic tetrad pattern was relatively unresponsive to stimulants and sensitive to depressants. Those subjects with the elevated Ma and Pd pattern were generally very responsive to stimulants and more sensitive to depressants than were the normal group and the group with the neurotic triad pattern. The group with the neurotic triad pattern was relatively responsive to stimulants, but less sensitive to depressants than were subjects with the psychotic tetrad or the elevated Ma and Pd pattern. The results are discussed in terms of Eysenck's theory of drug response based on an extroversion-introversion dimension. The group of subjects with the elevated Ma and Pd profile had personality scores on the MMPI, the California Psychological Inventory (CPI), and the Maudsley Personality Inventory (MPI) most suggestive of extroversion.