The laws about disclosing if a house is “haunted” vary from state-to-state.
Massachusetts
The possibility of a property being “psychologically impacted” isn’t considered a “material fact required to be disclosed” to potential buyers.
Virginia
Emotional defects like murders and ghost sightings only have to be disclosed if they physically affect the property (Blood running from the walls? Gotta tell the buyer).
California
As American Horror Story demonstrates, sellers do have to disclose emotional defects, but only in a very limited way. The state Civil Code requires that a death on the property only needs to be disclosed if it occurred less than three years prior to the sale and older incidents need to be addressed only if the buyer specifically asks. Some jurisdictions are a little more vague in the way they word things, so smart sellers could potentially disclose what they need to without having to drop words like “haunted,” “poltergeist” or “murder spree.”