One of the grounds which often leads people to suggest a will is not valid is if the deceased had suffered from dementia or Alzheimer’s disease. Both conditions are progressive, getting worse over time, and often it is easier to identify the onset of the illness with the benefit of hindsight (things which did not seem particularly noteworthy at the time can later be identified as symptoms of dementia). However, as case law shows, the mere fact that someone was suffering from dementia does not mean that they lack capacity to make a will. A recent example of this is the case of Lloyd v Jones  EWHC 1308 (Ch).
In 2005, Mrs. Harris made a will with the assistance of her niece, who was a retired GP. No solicitor was involved. The will appointed the niece and her husband as executors, made a bequest of £10,000 to her daughter and left the remainder of her estate to her son and his wife. The vast majority of the estate comprised a farm where Mrs Harris, her son and his wife had worked for many years.
In 2010, the deceased died and her daughter challenged the validity of the will on the grounds of capacity and lack of knowledge and approval (she argued that the deceased would not have been able to read the will because of her failing eyesight and that no-one had read it over to her). In respect of capacity, she argued that her mother began to suffer a decline in her mental faculties from about 2001, and by 2004 had been admitted to hospital suffering from confusion, forgetfulness and strange delusions (including, for example, that aliens were landing in her fields and that Saddam Hussein had poisoned her water supply). The son and his wife, and the niece and her husband argued that Mrs Harris had not really started to suffer from dementia until 2004 and that in any event, she had always intended to leave the farm to her son and the will was prepared on her specific instructions.
The Judge found that Mrs Harris had begun to suffer from dementia from around 2004, and her niece (as a former GP) would have recognised the signs and that she suffered from delusions and sometimes wandered in the night. However, this was not thought to be significant to her mental capacity. Delusions were only relevant if they affected the testamentary dispositions made, and here they do not – however bizarre they were, they did not have had any effect on the contents of the will. The Judge held that Mrs Harris had probably retained capacity to make a will during 2006 and possibly as late as 2007.
In respect of the want of knowledge and approval claim, it was held that Mrs. Harris would have been able to read the will, and would not have signed had she not read it. If she had read it, she would have understood it. It was short, simple and clear. The claim was therefore dismissed, and the will was deemed to be valid.
This case shows that it is possible for a testator to have quite a number of symptoms of dementia, but still to retain capacity to make a will. The condition rarely has a clear start date but progresses over time. Steps can, of course, be taken at the date of making a will to try to ensure that they have capacity (such as, for example, taking them to an experienced solicitor to make a will and obtaining a medical report on capacity). This may not prevent all disputes over capacity, but will certainly assist.