Differences in MMPI-2 FBS and RBS scores in brain injury, probable malingering, and conversion disorder groups: a...

Area of Science:

• Neuropsychology
• Psychological assessment

Background:

• Distinguishing genuine neurological conditions from malingering is crucial in clinical practice.
• The Minnesota Multiphasic Personality Inventory-2 (MMPI-2) offers scales to assess response validity.

Purpose of the Study:

• To evaluate the efficacy of the Symptom Validity Scale and Response Bias Scale (RBS) of the MMPI-2 in identifying invalid responding.
• To differentiate between individuals with traumatic brain injury (TBI), invalid TBI, and psychogenic non-epileptic seizures (PNES).

Main Methods:

• Compared raw scores on the MMPI-2 Symptom Validity Scale and RBS across three groups: valid TBI, invalid TBI, and PNES.
• Determined cutoff scores for each scale and assessed their classification accuracy.

Main Results:

• A Symptom Validity Scale cutoff of >30 identified 50% of invalid TBI cases with no misclassification of valid TBI or PNES groups.
• An RBS cutoff of >15 identified 50% of invalid TBI cases with <10% misclassification in other groups.
• Conjunctive use of both scales identified 44% of invalid TBI cases without misclassifying valid TBI or PNES groups.

Conclusions:

• The Symptom Validity Scale and RBS of the MMPI-2 show potential for detecting malingering in TBI and conversion disorder contexts.
• Further research is needed to validate these findings in larger, diverse populations.