The usefulness of the Minnesota Multiphasic Personality Inventory (MMPI-I) in predicting dropout from Cognitive Behavioural Therapy (CBT)

Background

Although treatment outcome relates directly to adherence to therapy, we do not know much on what kind of patients will remain in or dropout from treatment. Increased scores in the Paranoid “Pa” MMPI-I subscale seem to be a prognostic factor of dropout from therapy. Low scores in the “K” adjustment MMPI-I subscale also seem to be related to premature dropout from therapy. Also Patients with 1-3/3-1 and 2-7/7-2 combinations had significantly more dropout rates.

Materials and methods

Aim of the present study was to investigate personality factors that could predict dropout from Cognitive Behavioural Therapy using the three-point combinations of the ten clinical scales of Minnesota Multiphasic Personality Inventory (MMPI-I).

We studied 102 consecutive patients, with a variety of DSM-IV diagnoses, referred to a clinical psychologists' private practice and treated with CBT. Seventy-two (73.5%) patients completed CBT while twenty-seven patients (26.5%) dropped out of treatment early. All patients had completed MMPI-I just after their intake and evaluation interview. Treatment completers and treatment dropouts were compared using the 1-2-3, 1-3-4, 2-3-4, 2-4-7, 4-7-8 & 6-7-8 combinations, which are the more frequent combinations of the ten clinical scales of MMPI-I. Chi-square test (x2) was used.

Results

Not even one of the three-point combinations of the ten clinical scales of MMPI-I could predict treatment discontinuation.

Conclusions

Although MMPI-I is a well-known and widely used instrument in the assessment of personality; the three-point combinations of the ten clinical scales can't be used to predict patients in high risk of dropping out of therapy.