Relation of birth order and scores on measures of pathological narcissism

To study the relationship between birth order and pathological narcissism, it was predicted that firstborn and only children would score significantly higher on standardized measures of pathological narcissism. Two such measures, the Millon Clinical Multiaxial Inventory and the Narcissistic Personality Inventory, were administered to 50 randomly selected subjects from a metropolitan mental health and family treatment agency. Subjects were asked to indicate their ordinal birth positions, e.g., first, middle, last, or only, and then were administered both instruments. Analysis supported the initial prediction by indicating that firstborn and only children had higher mean scores on the measures of pathological narcissism. It might be advisable for clinicians to identify patients' ordinal positions while appraising relevant diagnostic criteria and eventual treatment planning.