Form C of the MHLC scales: a condition-specific measure of locus of control.

Form C of the Multidimensional Health Locus of Control (MHLC) scales is an 18 item, general purpose, condition-specific locus of control scale that could easily be adapted for use with any medical or health-related condition. Data from 588 patients with one of four conditions--rheumatoid arthritis, chronic pain, diabetes, or cancer--were utilized to establish the factor structure of Form C and to establish the reliability and validity of the resultant four subscales: Internality; Chance; Doctors; and Other (powerful) People. The alpha reliabilities of the subscales are adequate for research purposes. Data from the arthritis and chronic pain subjects established that the Form C subscales were moderately stable over time and possessed considerable concurrent and construct validity. Some discriminant validity of Form C with Form B of the MHLC was also demonstrated.