ADJ10788304 · July 29, 2026

The WCAB found that the WCJ's reliance on QME Dr. Mosby's opinion that the February 6, 2017 meeting was 55% of the cause of the psychiatric injury was not substantial medical evidence, and that the defendant failed to prove the good faith personnel defense.

From the decision · page 25Actual events of employment were predominant as to all causes combined of applicant’s cumulative trauma injury to his psyche (Lab. Code, § 3208.3, subd. (b)(1)), and included mandatory overtime and stressful situations on a day to day basis including incidents with inmates during his tenure as a correctional officer, and a February 6, 2017 meeting with two sergeants. 5. The opinion of Panel Qualified Medical Evaluator Robert Mosby, Ph.D., as to the percentage of causation of applicant’s psychiatric injury attributable to the February 6, 2017 meeting with two sergeants is not substantial medical evidence. 6. Given the subject matter and factual setting of this case, the February 6, 2017 meeting with two sergeants was not a “personnel action” taken against applicant. 7. Given the totality of the circumstances in this case, the February 6, 2017 meeting with two sergeants was not held in “good faith.” 8. Defendant failed to meet its burden of proof to establish that applicant’s cumulative trauma injury to his psyche is barred by the doctrine of “good faith personnel action” pursuant to section 3208.3, subdivision (h). (Lab. Code, § 3208.3, subd. (h) [“The burden of proof shall rest with the party asserting the issue.”].)

Dr. Mosby's opinion that the February 6, 2017 meeting was 55% of the cause of the psychiatric injury was based solely on the applicant's subjective perception during a single session.

Favours Applicant prevailed

This undermined the opinion's reliability and led to its rejection as substantial medical evidence.

From the decision · page 11(Def. Exh. I, QME Dr. Mosby report, October 10, 2022, p. 1, bold added.) The parties deposed QME Dr. Mosby on June 17, 2024. (Def. Exh. J, Zoom Deposition of Dr. Robert Mosby, June 17, 20124.) Dr. Mosby testified that the basis for assigning “at least 51%” of the cause of applicant’s psychiatric CT injury to the February 6, 2017 injury was applicant’s subjective perception during the one in-person session he had with applicant, that “he felt he would still be working there if they hadn’t done that to him. So that says to me it had quite a – that had quite an effect on him.” (Id., pp. 14-15.) Dr. Mosby also reiterated that he reviewed applicant’s Kaiser records and personnel file reflecting that applicant’s stress had definitely built over time as documented by mandatory overtime since 2014 and visits to Kaiser for stress and anxiety since 2015 (see App. Exh. 15, Mosby March 26, 2018 Report, pp. 3-4, supra). (Id., pp. 7-8, 20.) In fact, Dr. Mosby agreed that applicant had a compensable claim for psychiatric CT injury prior to the February 6, 2017 meeting. (Id., pp. 8-9, 16, 20-21.) When asked why the February 6, 2017 meeting was therefore “even relevant in terms of his condition,” Dr. Mosby responded as follows:

Dr. Mosby admitted the applicant's injury existed prior to the February 6, 2017 meeting and was due to ongoing workplace stress since at least 2014.

Favours Applicant prevailed

This showed the injury was not substantially caused by the meeting, weakening the defense's burden of proof.

From the decision · page 16(1968) 69 Cal.2d 408, 413, 416-17, 419 [33 Cal.Comp.Cases 660].) An opinion is not substantial evidence if it is based on “inadequate medical histories or examinations, on incorrect legal theories, or on surmise, speculation, conjecture, or guess.” (Escobedo v. Marshalls (2005) 70 Cal.Comp.Cases 604, 620-621 (Appeals Bd. en banc).) A medical opinion is not substantial evidence if it “poses a mere legal conclusion” that “does not furnish a basis for a finding...” (Granado v. Workmen’s Comp. App. Bd. (1968) 69 Cal.2d 399, 407 [33 Cal.Comp.Cases 647], citing Zemke v. Workmen’s Comp. Appeals Bd. (1968) 68 Cal.2d 794, 799 [33 Cal.Comp.Cases 358], superceded on other grounds.) Here, QME Dr. Mosby testified in 2024 that the only basis for his opinion that the February 6, 2017 meeting was 55% of the cause of applicant’s psychiatric CT injury was applicant’s own subjective and lay opinion that but for that meeting, he would still be working for defendant. On the other hand, Dr. Mosby also testified that applicant’s injury existed before the February 6, 2017 meeting and had, indeed, been the result of ongoing on-the-job stress since at least 2014 due to mandatory overtime and stressful situations in his workplace. (Def. Exh. J, Zoom Deposition of Dr. Robert Mosby, June 17, 2024, pp. 8-9, 16, 20-21; Def. Exh. I, p. 1.) In fact, Dr. Mosby stated

The February 6, 2017 meeting was not held in good faith and was not a personnel action sufficient to trigger the good faith personnel defense.

Favours Applicant prevailed

This negated the defense's claim that the injury was barred by Labor Code section 3208.3(h).

From the decision · page 25Therefore, even assuming arguendo that we agreed that the February 6, 2017 meeting was a “personnel action,” we cannot agree that the meeting was convened with “a sincere purpose” or without an intent to distract and mislead through manipulation and/or abuse of position. In other words, defendant failed to establish that any such “personnel action” was taken in “good faith.” Accordingly, the WCJ’s determination that defendant met its burden of proof to establish that applicant’s claim for psychiatric CT injury is barred by the “good faith personnel defense” (Lab. Code, § 3208.3, subd. (h)) is not based on substantial evidence.

Dr. Mosby opined that the February 6, 2017 meeting with two sergeants was 55% of the cause of applicant's psychiatric cumulative trauma injury, but his opinion was found not to be substantial medical evidence due to reliance on applicant's subjective perception and inadequate examination.

Dr. Mosby's opinion was based primarily on the applicant's subjective statements during a single session and lacked substantial medical evidence support, leading to its rejection.

From the decision · page 11(Def. Exh. I, QME Dr. Mosby report, October 10, 2022, p. 1, bold added.) The parties deposed QME Dr. Mosby on June 17, 2024. (Def. Exh. J, Zoom Deposition of Dr. Robert Mosby, June 17, 20124.) Dr. Mosby testified that the basis for assigning “at least 51%” of the cause of applicant’s psychiatric CT injury to the February 6, 2017 injury was applicant’s subjective perception during the one in-person session he had with applicant, that “he felt he would still be working there if they hadn’t done that to him. So that says to me it had quite a – that had quite an effect on him.” (Id., pp. 14-15.) Dr. Mosby also reiterated that he reviewed applicant’s Kaiser records and personnel file reflecting that applicant’s stress had definitely built over time as documented by mandatory overtime since 2014 and visits to Kaiser for stress and anxiety since 2015 (see App. Exh. 15, Mosby March 26, 2018 Report, pp. 3-4, supra). (Id., pp. 7-8, 20.) In fact, Dr. Mosby agreed that applicant had a compensable claim for psychiatric CT injury prior to the February 6, 2017 meeting. (Id., pp. 8-9, 16, 20-21.) When asked why the February 6, 2017 meeting was therefore “even relevant in terms of his condition,” Dr. Mosby responded as follows:

E.L. Yeager Construction v. Workers’ Comp. Appeals Bd. (Gatten) (2006) 145 Cal.App.4th 922, 928

A medical opinion must be predicated on reasonable medical probability and be supported by substantial evidence to be relied upon in workers' compensation decisions.

The WCAB applied this standard to reject Dr. Mosby's opinion as not substantial medical evidence because it was based on conjecture and inadequate examination.

From the decision · page 16A. “Substantial Cause” Following the April 2022 decision in the applicant, defendant had the opportunity to further develop the record to meet its burden of proof to establish that the February 6, 2017 meeting was a “good faith personnel action” and that it was the “substantial cause” of applicant’s psychiatric CT injury. Despite this opportunity, the medical record developed following the applicant creates more doubt as to the opinion of QME Dr. Mosby on the issue of “substantial cause” under section 3208.3, subdivision (h), than existed prior to our decision in the applicant. As a result, the WCJ’s decision to rely on Dr. Mosby’s opinion that the February 6, 2017 meeting was either “more than 51%” or 55% of the cause of applicant’s psychiatric CT injury and thus, the “substantial cause” of the injury pursuant to section 3208.3, subdivision (h), is not based on substantial medical evidence. A decision of the Workers’ Compensation Appeals Board must be supported by substantial evidence. (Lab. Code, § 5952(d); Lamb v. Workmen’s Comp. Appeals Bd. (1974) 11 Cal.3d 274, 280-81 [39 Cal.Comp.Cases 310].) To be considered substantial evidence, a medical opinion “must be predicated on reasonable medical probability.” (E.L. Yeager Construction v. Workers’ Comp. Appeals Bd. (Gatten) (2006) 145 Cal.App.4th 922, 928 [71 Cal.Comp.Cases 1687]; McAllister v. Workmen’s Comp. Appeals Bd.

Applicant's subjective perception during a single session with QME Dr. Mosby that the February 6, 2017 meeting was a significant cause of his injury

From the decision · page 11(Def. Exh. I, QME Dr. Mosby report, October 10, 2022, p. 1, bold added.) The parties deposed QME Dr. Mosby on June 17, 2024. (Def. Exh. J, Zoom Deposition of Dr. Robert Mosby, June 17, 20124.) Dr. Mosby testified that the basis for assigning “at least 51%” of the cause of applicant’s psychiatric CT injury to the February 6, 2017 injury was applicant’s subjective perception during the one in-person session he had with applicant, that “he felt he would still be working there if they hadn’t done that to him. So that says to me it had quite a – that had quite an effect on him.” (Id., pp. 14-15.) Dr. Mosby also reiterated that he reviewed applicant’s Kaiser records and personnel file reflecting that applicant’s stress had definitely built over time as documented by mandatory overtime since 2014 and visits to Kaiser for stress and anxiety since 2015 (see App. Exh. 15, Mosby March 26, 2018 Report, pp. 3-4, supra). (Id., pp. 7-8, 20.) In fact, Dr. Mosby agreed that applicant had a compensable claim for psychiatric CT injury prior to the February 6, 2017 meeting. (Id., pp. 8-9, 16, 20-21.) When asked why the February 6, 2017 meeting was therefore “even relevant in terms of his condition,” Dr. Mosby responded as follows:

Dr. Mosby's limited contact with applicant and reliance on subjective statements rather than comprehensive medical evidence

From the decision · page 18Dr. Mosby’s deferral is not surprising given the uncertainty in his own opinion. In fact, the reasons he cites for his deferral to Dr. Staehle undermines the very foundation of his own opinion on the issue. In other words, Dr. Mosby inherently admits that his opinion on the question of “substantial causation” is based on conjecture and inadequate examination of the patient; therefore, his opinion cannot be relied on as substantial medical evidence. (Escobedo, supra; Granado, supra.) 4 Therefore, the opinion of QME Dr. Mosby that the February 6, 2017 meeting was 55% of the cause of applicant’s psychiatric CT injury is not substantial medical evidence. As a result, and regardless of whether the meeting was a “good faith personnel action” or not, defendant failed to meet its burden of proof to establish its affirmative defense under section 3208.3, subdivision (h).