The tort of negligent infliction of emotional distress (NIED) is a controversial cause of action, which is available in nearly all U.S. states but is severely constrained and limited in the majority of them.
If one fails in this duty and unreasonably causes emotional distress to another person, that actor will be liable for monetary damages to the injured individual.
NIED began to develop in the late nineteenth century, but only in a very limited form, in the sense that plaintiffs could recover for consequential emotional distress as a component of damages when a defendant negligently inflicted physical harm upon them.
However, NIED started developing into its more mature and more controversial form in the mid-20th century, as the new machines of the Second Industrial Revolution flooded the legal system with all kinds of previously unimaginable complex factual scenarios.
Courts began to allow plaintiffs to recover for emotional distress resulting from negligent physical injuries to not only themselves, but other persons with whom they had a special relationship, like a relative.
Twelve years after Dillon, California expanded NIED again, by holding that a relative could recover even where the underlying physical injury was de minimis (unnecessary medications and medical tests) if the outcome was foreseeable (the breakup of the plaintiffs' marriage as a result of the defendants' negligent and incorrect diagnosis of a sexually transmitted disease).
In 1999, Hawaii took NIED even further by expressly holding that "damages may be based solely upon serious emotional distress, even absent proof of a predicate physical injury.
A corollary of this critique is that the tort runs the risk (in the bystander NIED context) of overcompensating plaintiffs for distress which would have occurred anyway regardless of the cause of death of the decedent.
In a landmark decision of the Supreme Court of California which severely limited the availability of bystander NIED, Associate Justice David Eagleson wrote in Thing v. La Chusa, 48 Cal.