Relationships between MMPI codetypes and MAC scale elevations in adolescent psychiatric samples

This study investigated the relationship between subjects' MacAndrew Alcoholism Scale (MAC) elevations and their placement in various codetype classifications. The sample consisted of 1,347 adolescents receiving psychiatric services in Missouri, Virginia, or Texas. The frequency of MAC scores greater than or equal to 24 and greater than or equal to 28 was evaluated, separately by gender, for single-scale and two-point codetypes, containing a minimum of at least 10 subjects. Marked differences occurred in the frequency of MAC scale elevations depending on the adolescent's codetype classification. MAC scores for both genders, for example, were most frequently elevated for the 4-9/9-4 codetype and more rarely elevated for the 2-3/3-2 codetype. Results are discussed in terms of potential measurement overlap which may occur between the MAC scale and several MMPI standard clinical scales, including 4, 6, and 9. It was also noted that the sensitivity and specificity of the MAC scale may vary in relation to subjects' clinical scale profile characteristics.