What did Breunig decide about insanity and negligence?

A sudden mental delusion may excuse negligence only if it strikes without warning. If the driver had prior notice of such episodes, liability can follow.

Why was the insurer liable here?

The jury found negligence because evidence showed the driver had signs of mental trouble earlier; with forewarning, she should not have driven.

Is a delusion like a heart attack for legal excuse?

No. The court distinguished sudden physical events from mental delusions. Only delusions without prior warning can be a complete excuse.

What is the practical rule for drivers?

If you know of seizures or delusions that could suddenly impair driving, you must not drive; otherwise you may be negligent if an accident happens.

Breunig v. American Family Insurance

Breunig v. American Family Insurance 173 N.W.2d 619 (Wis. 1970)

Mental Delusion & Negligence — easy, classroom-style English.

Wisconsin Supreme Court 1970 Citation: 173 N.W.2d 619 Tort / Negligence Reading: ~6 min Location: India (Explainer)

CASE_TITLE: Breunig v. American Family Insurance PRIMARY_KEYWORDS: insanity defense, mental delusion, negligence SECONDARY_KEYWORDS: prior warning, sudden incapacity, automobile accidents AUTHOR_NAME: Gulzar Hashmi PUBLISH_DATE: 2025-10-31 Slug: breunig-v-american-family-insurance

Quick Summary

Breunig v. American Family Insurance asks when a driver’s mental delusion can excuse negligence. Veith claimed a sudden delusion—believing God controlled the wheel and she could fly—made her lose control and crash. The Court said: a sudden mental event without warning can excuse liability, but if the driver had prior notice of such tendencies, driving is negligent. The verdict for the plaintiff was affirmed.

Mental Delusion Prior Warning Road Negligence Standard of Care Insurance Liability

Issues

Did Veith have previous knowledge of her susceptibility to delusions making it negligent to drive?
Can sudden insanity, without warning, excuse a driver from negligence?

Rules

Insanity & Negligence: Not every kind of insanity excuses negligence. Only a sudden mental event that strikes without warning may do so.
Prior Notice Rule: If the driver had reason to foresee loss of control from mental issues, driving is negligent.

Facts (Timeline)

Timeline illustration for Breunig v. American Family Insurance

Driving in Center Lane

Veith drove in the center lane, then suddenly turned into the plaintiff’s lane and collided.

Sudden Delusion

She later stated she believed God took the wheel and that she could “fly” like Batman; she pressed the accelerator toward a truck.

Psychiatric Account

To her psychiatrist, she described the episode as sudden and overpowering—no conscious control at the moment.

Suit Filed

The plaintiff sued the insurer for negligence and damages.

Arguments

Plaintiff

Veith had prior signs of mental problems; she should not have driven.
Her delusion was foreseeable to her; negligence is established.
Insurer must cover the loss caused by the insured’s negligence.

Defendant

The delusion was sudden and without warning—like an unforeseeable seizure.
A sudden insanity should excuse liability for negligence.
No breach because control was lost instantly.

Judgment

Trial court judgment for the plaintiff affirmed. The court accepted that sudden insanity can sometimes excuse negligence, but only where there is no prior warning. On the facts, there was evidence of earlier mental issues, so negligence could be found.

Result: Liability upheld against the insured; insurer responsible.

Ratio Decidendi

A driver is not negligent if a mental delusion strikes without any forewarning and causes instant loss of control. If prior susceptibility is known or reasonably knowable, driving anyway is negligent.

Why It Matters

Sets a clear line between sudden insanity (no warning) and known mental risks (warning → negligence).
Guides courts on mental states in road accidents and insurance claims.
Promotes safety: people with known episodes should not drive.

Key Takeaways

Sudden delusion without warning can excuse negligence.
Prior warning or history → duty not to drive.
Insurers answer for insured’s negligent driving.

Insanity defense in tort is narrow and fact-specific.
Comparisons to physical episodes (heart attack) are limited.
Evidence of earlier symptoms is crucial.

Mnemonic + 3-Step Hook

Mnemonic: “ W.A.R.”

Warning? If yes, don’t drive.
Abrupt delusion without warning can excuse.
Responsibility returns when risks were known.

IRAC Outline

Issue

Whether Veith’s delusion, given evidence of prior mental issues, excuses negligence in the car crash.

Rule

Sudden insanity may excuse negligence only if it comes without forewarning; prior susceptibility makes driving negligent.

Application

Evidence suggested earlier mental problems; the jury could find Veith knew or should have known not to drive.

Conclusion

Negligence found; judgment for plaintiff affirmed; insurer liable under the policy.

Glossary

Sudden Insanity: A mental state that erupts without warning and causes instant loss of control.
Forewarning: Any prior knowledge or sign that a dangerous condition may occur.
Negligence: Failure to use the care a reasonable person would use in similar circumstances.