MENTAL pain or anxiety the law cannot value, and does not pretend to redress, when the unlawful act complained of causes that alone. Lord Wensleydale's famous dictum in Lynch v. Knight will serve as a starting point for this discussion. His lordship's notion of mental pain is evidently that of a "state of mind" or feeling, hidden in the inner consciousness of the individual; an intangible, evanescent something too elusive for the hardheaded workaday common law to handle. Likewise, in that very interesting problem regarding recovery for damages sustained through fright, it is always assumed, tacitly or expressly, that mere fright, alone, creates no cause of action. "The mere temporary emotion of fright not resulting in physical injury is, in contemplation of law, no injury at all, and hence no foundation of an action," says Professor Throckmorton in his admirable discussion in a recent number of the Harvard Law Review.
Goodrich, Herbert F. "Emotional Disturbance as Legal Damage." Mich. L. Rev. 20 (1922): 497-513.