The MMPI-168(L) and ADD in assessing psychopathology in individuals with mental retardation: between and within instrument associations.
The MMPI-168(L) and ADD rarely agree—use them only as part of a fuller assessment battery.
01Research in Context
What this study did
Putnam et al. (2003) compared two paper-and-pencil tests that screen for mental-health problems in adults with intellectual disability.
They looked at how well the MMPI-168(L) and the ADD agreed with each other.
The team wanted to see if scores on one test matched scores on the other for the same person.
What they found
Only the Mania scale lined up across both tools.
All other scales showed weak or no overlap.
The authors say the two tests should not be used alone to decide if someone has a psychiatric disorder.
How this fits with other research
Madden et al. (2003) and McLennan et al. (2008) found better news. Their tools, the ADAMS and the adapted HADS, showed strong or adequate agreement with other mood measures.
Lecavalier et al. (2006) explain why: Likert-type scales like parts of the MMPI only work when you add pictures, simple words, and pretests. Without those supports, validity drops.
So the poor fit F et al. saw is not a flaw in all ID tools—it is a red flag that the MMPI-168(L) and ADD lack the design features that later research shows are essential.
Why it matters
If you screen adults with ID for mood or behavior issues, do not rely on just one questionnaire. Pair a brief tool with caregiver interview, direct observation, and recent behavior history. Pick instruments that include pictures or plain-language anchors, and save the MMPI-168(L) and ADD for research only.
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02At a glance
03Original abstract
An abbreviated version of the Minnesota Multiphasic Personality Inventory, the MMPI-168(L), modified for use with clients who have moderate or mild mental retardation, was administered to 58 clients, most of whom had co-existing dual psychiatric diagnoses. Another recently developed instrument, the Assessment of Dual Diagnosis (ADD), was administered by interviewing a knowledgeable care giver. Correlations were examined among the raw scores on the 13 ADD scales and T scores of the 13 MMPI-168(L) scales. Contrary to expectations few correlations were found between the scales of the two instruments including scales purported to assess similar psychological constructs. The major exception was the Mania scale of the MMPI-168(L), which correlated moderately well with the Schizophrenia and Dementia scales of the ADD. Client age correlated strongly and negatively with scores on the Conduct Disorder and Sexual Disorder scales of the ADD. Finally, intra-instrument scale correlations were surprisingly large and, from a clinical and diagnostic perspective, meaningful. However, the large number of intra-instrument correlations showed that the scales of both instruments possess considerable overlap, which could make differential diagnosis problematic. It is suggested that it might be necessary to administer both instruments, and carefully consider behavioral history, to accurately diagnose psychiatric disturbances or personality characteristics of individuals with mental retardation.
Research in developmental disabilities, 2003 · doi:10.1016/s0891-4222(02)00170-1