The Treating Psychologist Asked to Prove Causation
Dr. L. has treated Ms. C., 41, for 14 months after a rear-end collision. Ms. C. reports nightmares, avoidance, hypervigilance, and blank stretches she calls lost weeks. Her psychiatrist diagnosed PTSD and major depression. Opposing counsel subpoenas Dr. L.s records and asks her to serve as the plaintiffs expert on causation, permanence, and future care costs. Dr. L. administers the MMPI-2-RF (F-r T = 78, Fp-r T = 85, Fs T = 71, RBS T = 80, RCd T = 72, EID T = 66) and the PCL-5 (61). Ms. C. is in active litigation, has applied for Social Security disability, and her sister describes her as having always been dramatic. Dr. L. also notes that Ms. C. has not worked since the crash, does the familys grocery shopping weekly, and drives herself to appointments. Dr. L. asks whether she should accept the expert role and how to write up the test data.
1. What can and cannot be concluded from the elevated F-r, Fp-r, Fs, and RBS scores?
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These are overreporting indicators, not malingering tests, and the distinction matters in a personal injury case.
- F-r is a broad infrequency scale; it rises with genuine severe psychopathology, distress, and chaotic life circumstances as well as with exaggeration.
- Fp-r is the best-validated indicator of feigned or grossly exaggerated psychopathology. At T = 85 it is clinically meaningful, but it is not immune to false positives in people with genuine psychotic-spectrum or highly distressed presentations.
- Fs and RBS were developed against somatic and cognitive response-bias criteria. Both are known to be elevated in people with genuine neurological injury, chronic pain, and head trauma, so an elevated RBS in a collision claimant is not equivalent to feigning memory loss. RBS elevations have, however, been associated with failure on performance validity tests, so the cognitive complaint needs direct testing.
- PCL-5 = 61 is a self-report symptom measure with no validity scale; it documents reported symptoms, not their credibility or their cause.
Statistical caution applies here: even a fairly specific index produces substantial false positives when the base rate of feigning is low, as it typically is in unselected injury claimants. Positive predictive value depends on prevalence. The defensible conclusion is a diagnosis with a documented caution about possible overreporting, not an assertion that she is malingering.
2. Should Dr. L. accept the expert role? What alternatives and conditions should be considered?
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This is a dual-role problem, and the rule of thumb in forensic practice is to avoid it.
Risks of accepting
- The therapeutic alliance creates a pull toward advocating for the patient; the treating clinician has 14 months of invested effort and a treatment frame built on believing the patient's account.
- Dr. L. is also the records custodian under subpoena; combining that with expert testimony multiplies exposure.
- An opinion on causation, permanence, and future care costs requires methods and knowledge (accident reconstruction, pre-injury baseline, cost-of-care data) that treatment does not generate.
- Opposing counsel will highlight that Dr. L. never conducted performance validity testing for the memory complaints before forming opinions.
Her options
- Decline the expert role, continue treatment, and testify only as a treating fact witness about diagnosis and course, expressly not about causation or costs.
- Help the patient retain an independent psychologist or neuropsychologist for a forensic evaluation with appropriate validity testing.
If she proceeds anyway, she must clarify the role in writing, obtain informed consent explaining that confidentiality is limited and that the opinion serves the court, avoid opinions beyond her data, and disclose all test scores including the overreporting indices rather than selectively reporting.
3. How should behavioral observations and response bias be handled in the written report?
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Report the pattern honestly rather than resolving it in either direction, and let the reasoning be visible.
The observations that matter: she has not worked, yet grocery shops weekly and drives herself; that is inconsistent with the most severe end of the claimed cognitive and avoidant symptoms, though not dispositive. She is in litigation and applying for disability, both of which create incentive and are normal contextual facts rather than proof of deception. The sister's characterization is collateral opinion of limited weight.
A defensible report states: (a) the PTSD and depressive symptom picture and its documented course; (b) that MMPI-2-RF Fp-r and RBS are elevated, with an explanation of what those scales measure and their limitations in injury populations; (c) that no performance validity testing was conducted, so cognitive complaints are unverified; (d) that the PCL-5 documents reported symptoms only; and (e) that a formal response-bias determination cannot be made from treatment data.
On causation, distinguish onset and course from cause: a temporal relationship to the collision is documented in her notes, but apportioning between the collision, pre-existing adjustment difficulties, and litigation stress requires a methodology treatment does not supply. Recommend an independent medico-legal assessment. Crucially, do not silently omit the validity data; selective reporting is both an ethical problem and, once exposed on cross-examination, a credibility problem that taints the legitimate parts of the report.