Wills, Testamentary Capacity, and Undue Influence IRWIN N. PERR, MD, JD Psychiatrists, sophisticated in law and psychiatry, are usually acquainted with the issue of testamentary capacity. Wills are legal instruments by which persons dispose of property after death in accordance with their wishes. Wills are created at the time of the making of the will; they become effective at death unless revoked or succeeded by a later will before death. One of the necessary elements in the making of a will is the mental capacity to do so at the time that it is prepared. If a person did not have the necessary capacity to make a last testament (testamentary capacity), then the will will be declared void. Wills are presumed to be valid if they conform with the technicalities required by law; those who would contest a will have the burden to demonstrate a lack of capacity by the deceased. This lack of capacity is usually shown by the presence of a mental disease at the time of the making of a will of such a degree that the testator does not know that a will is being made or the extent of the bounty or property owned or even the identity and relationship of those who, under ordinary circumstances, would be the recipients of the testator's largesse. Some states also specifi- cally require an ability to communicate one's desire in the creation of a will. Generally, if a person is unable to communicate orally, in written fashion or by behavior his wishes, then that person will not be considered competent to make a will. The psychiatric correlates of will-making have been extensively noted in psychiatric journals and texts. The issue of undue influence, to the contrary, is one that usually receives little or no attention, yet it is important in that a mental condition that does not reach the level necessary to justify a finding of testamentary incapacity may, in combination with other circumstances, result in the voiding of a will. DEFINITION OF UNDUE INFLUENCE The essence of undue influence invalidating a will is that the influence of another person must be such that it substitutes the wishes of that other person for that of the testator. In other words, the undue influence must destroy the free agency of the testator and substitute that of another. The motivation behind the influencing is irrelevant. If one influences another by kindness and good deeds or if one persuades another fairly and reasonably without fraud or deception, then the effect is not one of undue influence. There must be more than friendly advice or flattery. There must _________ Dr. Perr is Professor of Psychiatry and Profesor of Environmental and Community Medicine at the Rutgers Medical School-CMDNJ, Piscataway, NJ. This paper was presented at the Annual Meeting of the American Academy of Forensic Sciences on Oct. 17, 1980.