Terms used in this title, unless the context otherwise plainly requires, shall mean:
The term does not include a mental injury arising from emotional, mental, or nonphysical stress or stimuli. A mental injury is compensable only if a compensable physical injury is and remains a major contributing cause of the mental injury, as shown by clear and convincing evidence. A mental injury is any psychological, psychiatric, or emotional condition for which compensation is sought;
SDCL 62-1-1