Does depression explain poor effort on Symptom Validity Tests (SVT)?

Abstract

Background and aims

Valid assessments require sufficient effort from the part of the testee. Motivation may be compromised, particularly in psychiatric conditions. We examined associations between response bias on free recall and self-reported symptoms in depressed and PTSD patients.

Participants and methods

This is a cross-sectional study. Patients had depression (n = 48), or PTSD or other anxiety disorders (n = 37). A control group (n = 47%) had chronic pain disorder, fibromyalgia or chronic fatigue. The Green Word Memory Test (GWMT) was administered to all subjects. The Structured Inventory of Malingered. Symptomatology (SIMS), and the Beck Depression Inventory (BDI-II) were administered in subsamples. Study outcome was self-reported depressive symptoms in Symptom Validity Test (SVT) negative cases.

Results

Average age of the participants was 45.1 years (SD 9.5), 48.5% were female. GWMT was positive in 52.3% of all cases, GWMT and SIMS were positive in 33.8%, and GWMT and SIMS were negative in 37.7%. No significant group effects on GWMT were found. Average BDI-II scores were 32.8 (SD 13.9) for depressed patients, 28.3 (15.5) for those with anxiety disorders, and 27.6 (14.1) for controls (P = 0.43). Seventy-eight percent of depressed GWMT negative cases reported at least moderate depressive symptoms (BDI-II > 18), and 44.4% severe symptoms (BDI-II > 29). Approximately half of the GWMT negative cases with anxiety disorders and controls scored BDI-II > 18.

Conclusions

Non credible test performance is prevalent in disability claimants with affective, mood disorders. However, depressive symptoms per se do not explain poor effort on cognitive tasks.

Disclosure of interest

The authors have not supplied their declaration of competing interest.