The relation between symptom validity testing and MMPI-2 scores as a function of forensic evaluation context

Area of Science:

• Forensic Psychology
• Psychological Assessment
• Clinical Psychology

Background:

• Symptom validity testing (SVT) is crucial in forensic evaluations to detect exaggerated or feigned symptoms.
• The Minnesota Multiphasic Personality Inventory-2 (MMPI-2) is frequently used in forensic settings, but its utility in identifying non-credible presentations requires further investigation.
• Distinguishing genuine symptoms from exaggerated ones is vital for accurate competency and disability assessments.

Purpose of the Study:

• To investigate the association between MMPI-2 scale scores and symptom validity test (SVT) failure in forensic populations.
• To determine the effectiveness of specific MMPI-2 scales, such as the Fake Bad Scale (FBS) and F(P) scale, in identifying non-credible symptom presentation.
• To compare the utility of MMPI-2 scales in detecting SVT failure across different forensic contexts (criminal defendants vs. civil litigants).

Main Methods:

• The study analyzed data from 127 criminal defendants and 141 civil litigants undergoing forensic evaluations.
• MMPI-2 scale scores were correlated with failure on cognitive symptom validity tests (SVTs).
• Analyses examined the association of the MMPI-2 Fake Bad Scale (FBS) and F(P) scale with SVT failure in both groups.

Main Results:

• SVT failure was associated with exaggerated somatic complaints in civil litigants and broader psychopathology exaggeration in criminal defendants.
• MMPI-2 FBS scores were significantly associated with SVT failure in both civil and criminal litigants.
• The MMPI-2 F(P) scale was associated with SVT failure in criminal defendants but not in civil plaintiffs.

Conclusions:

• The MMPI-2 FBS is a valuable tool for identifying non-credible presentations of somatic and cognitive complaints in both civil and criminal forensic assessments.
• The MMPI-2 infrequency scales' association with SVT failure appears limited to criminal forensic settings.
• These findings support the use of specific MMPI-2 scales to enhance the validity of forensic psychological evaluations.