In an attempt to provide further information on the functions of the serotonergic system in humans, we investigated the possible correlation between a peripheral serotonergic marker. such as platelet H-3-imipramine binding, and the Minnesota Multiphasic Personality Inventory (MMPI) items and scales in a group of 20 healthy subjects. The results showed the presence of significant positive correlation between the maximum binding capacity. a measure of the number of H-3-imipramine sites, and 17 MMPI items suggestive of personality features of self-certainty. feeling of well-being and sense of reality.