Whether contractual incapacity requires proof of a medically diagnosed mental illness or defect that is permanent, progressive, degenerative, or long-standing.
Holding
No. A party may in principle establish contractual incapacity based on a mental condition that is temporary or limited to the time of the transaction; the dispositive inquiry concerns capacity at the time of contracting.
Reasoning
A settlement agreement is a contract, and general contract principles govern its enforceability. A party seeking to avoid a contract bears the burden to prove that mental illness or defect rendered that party incapacitated when the agreement was made.
Massachusetts recognizes two routes to contractual incapacity. Under the traditional cognitive test, the party must have been unable to understand the nature and quality of the transaction or to grasp its significance and consequences. Under the modern affective or volitional test, a party who retains some understanding may still avoid the contract if mental illness or defect prevented reasonable action in relation to the transaction and the other party had reason to know of that condition.
The Court rejected the Appeals Court's suggestion that incapacity can be shown only through a permanent, progressive, degenerative, or long-term diagnosed disorder. Modern understandings of mental illness recognize that a disabling condition may be temporary. The focus remains on the person's functional capacity at the particular time of the transaction, not on how long the condition has existed or whether it will continue.