Most states base testamentary capacity -- the mental competency to make a will -- on three criteria. The testator, person who creates a will, must understand that she is directing the transfer of her property after her death. She must possess an awareness of what property she owns, and she must be able to identify her family members, whether she mentions them in her will or omits them. These are relatively easy criteria to meet. For example, if your loved one wrote you out of her will days before her death because of an imagined slight that occurred only in her own mind, the court will probably not invalidate her will on grounds of testamentary incapacity. Right or wrong, she possessed an understanding of what she was doing.
Mental incompetence resulting from a physical condition is usually more definitive and easier to assess. Some states, such as California, include provisions in their statutes for these situations, separate from legislation addressing testamentary capacity. However, these laws also possess loopholes. If the testator writes her will in March, then her physician diagnoses her with Alzheimer’s in October, she was technically of sound mind at the time she created her will. You may not win a will contest if you try to prove otherwise. If she was clear-headed, then immediately experienced a confused spell right after she signed, her condition might not be enough for a court to invalidate her will.
Time is usually of the essence if you want to contest a will. Although deadlines vary among states, you must generally file a legal action with the court very soon after the will’s executor submits it for probate. Some states, such as New Jersey, require you to file an objection to the will, called a caveat, even before the executor submits the will for probate. State laws usually also restrict who can contest a will. You must have "standing" -- for example, if you’re so closely related to the decedent that you would have inherited had she not left a will or if she mentioned you in the will specifically to disinherit you. After you file your objection or challenge, the court schedules a trial to decide whether it has merit.
Will contests are complex legal procedures, particularly when you’re claiming the testator was mentally incompetent. Your chances of success usually increase if you enlist the help of an attorney. You must produce irrefutable legal proof of your loved one’s mental condition, and its timing is critical. You’ll probably need the testimony of witnesses who can state, for example, that your loved one did not know you or recognize you within days of signing her will, regardless of the fact that she gave birth to you. Witnesses can also document bizarre behavior on the part of your loved one, occurring within days of the date of the will. If you can produce a previous will that seems relatively normal, this might offer additional proof that your loved one was not of sound mind when she replaced it with one that seems inexplicable.