Lack of testamentary capacity is one possible reason to contest a loved one’s will. Typically, this ground is considered when a recently deceased loved one had senility, dementia, insanity or was under the influence of a substance. However, many people do not fully understand the requirements for someone to lack testamentary capacity.

Testamentary capacity refers to the mental competence required to legally sign a will. To challenge a will on the ground of testamentary capacity, you must generally prove that your loved one was unable to understand the effects of signing the will at the time it was signed.

California law determines when someone lacks testamentary capacity

According to California probate code, your loved one may not have been mentally competent to sign a will if, at the time the will was signed, he or she:

  • Could not understand what the effects would be for signing the will
  • Could not remember or understand the value of his or her property
  • Could not remember his or her relationship to living decedents or others who are affected by the will

Your loved one also may not have been competent to sign a will if he or she had, at the time the will was signed, a mental disorder that involved delusions or hallucinations. However, these delusions or hallucinations must have affected how your loved one chose to distribute property.

Proving that a loved one lacked testamentary capacity can be difficult. Regardless of the reason, contesting a loved one’s will can also be expensive and time-consuming. However, there are instances when contesting a will is an appropriate choice. Sometimes, contesting a will can be the best way to ensure that your loved one’s true wishes are being granted and your interests are being protected.