Before a psychiatric injury can be treated as work-related, it has to clear a compensability bar that is higher than the standard for a physical injury. That bar is set by §3208.3the California Labor Code section governing the compensability of psychiatric injury. Understanding exactly what it requires is the foundation for everything a clinician later writes about causation.
The core rule is the predominant-cause standard: a psychiatric injury is compensable only if actual events of employment are the predominant cause — more than 50% — of all combined causes of the psychiatric injury. This is the single most misread phrase in the statute.
"Predominant" does not mean the biggest single contributing factor. It means a majority of all causes combined. If work accounts for 40% and four other factors split the remaining 60%, work is the largest single cause yet still fails the standard — because it is not more than half of everything combined.
Two qualifiers shape who can even bring such a claim. The six-month employment rule generally requires that a worker have at least six months of employment before a mental-mental claim (a psychiatric injury with no physical cause) will be considered — unless the injury was caused by a sudden and extraordinary employment event, in which case the six-month requirement does not apply. A second qualifier lowers the bar in specific circumstances: when the worker was the victim of, or was directly exposed to, a violent act, a lower substantial-cause threshold of roughly 35–40% applies instead of the predominant-cause standard.
The teaching case shows the standard met cleanly. Sofia Reyes, a paramedic, witnessed a fatal multi-vehicle collision in the course of her work, including a pediatric fatality she could not save. The psychologist's apportioned opinion attributes 70% of the causation to work exposure. Because work exposure exceeds 50% of all combined causes, the injury is industrial — compensable under the predominant-cause standard. (Her exposure to a violent, traumatic event would also satisfy the lower threshold, but it isn't needed here; the predominant-cause bar is already cleared.)
The clinician's job is not to memorize a number but to internalize the arithmetic: every contributing cause is weighed, and work has to win a majority of the whole.
A psychiatric injury claim attributes 45% of causation to work events and the remaining 55% to four personal stressors. Under the predominant-cause standard, is the injury industrial?