What Is California Labor Code §3208.3: the Mental Stress / Psychiatric Injury Standard?

What is the predominant-cause standard?

The worker usually must prove actual work events caused more than half of the psychiatric injury when all causes are combined.

Predominant cause is a medical-legal percentage analysis. The evaluator should identify each real cause, assign causation where possible, and explain why work does or does not cross the threshold. A vague report that says stress came from work may not be enough.

Workers can help by building a clear timeline. Keep incident reports, texts, emails, schedules, threat reports, harassment complaints, treatment records, and witness names. The facts must match the medical history.

What is the six-month employment rule?

Most psychiatric injury claims require at least six months of employment with the employer, but the months need not be continuous.

The statute bars many short-employment psychiatric claims. The rule does not require six continuous months, but the worker must meet the minimum unless an exception applies. A sudden and extraordinary employment condition can bypass the six-month rule.

Examples need careful review. A routine stressful workplace is different from a violent robbery, serious crash, explosion, or other extraordinary event. The facts, not the label, decide the exception.

How does the personnel-action defense work?

A lawful, nondiscriminatory, good-faith personnel action can block compensation if it substantially caused the psychiatric injury.

Discipline, demotion, transfer, performance review, investigation, or termination can trigger the defense. The employer has the burden on that issue. The worker may still challenge whether the action was lawful, nondiscriminatory, and in good faith.

Claims based on harassment, violence, unsafe events, or conduct outside normal personnel management need a separate analysis. The defense should not be accepted at face value.

What is different about violent acts?

For certain violent-act claims, the statute lowers the causation threshold from predominant cause to substantial cause.

When the worker is a victim of a violent act or is directly exposed to a significant violent act, the causation standard is lower. The statute defines substantial cause as at least 35 to 40 percent from all sources combined.

This rule can matter for assaults, robberies, shootings, severe threats, or direct exposure to catastrophic injury. The worker still needs a proper diagnosis and a medical report that applies the right standard.