How do we deal with Dad's dementia delusions?

Daughterann asked...

How do we deal with Dad's dementia delusions? My dad has severe dementia and has been getting more and more suspicious and agitated. When my mom leaves the house to run errands, he's often convinced she's having an affair. He believes she and I are taking money from him and will leave him destitute. When I try to reassure him that there's no truth to any of this by showing him the checkbook or telling him specifically where my mom is going, he only gets angrier. What can I do?

Expert Answer

Kenneth Robbins, M.D., is a senior medical editor of He is board certified in psychiatry and internal medicine, has a master's in public health from the University of Michigan, and is a clinical professor of psychiatry at the University of Wisconsin-Madison. His current clinical practice focuses primarily on geriatrics. He has written and contributed to many articles and is frequently invited to speak on psychiatric topics, such as psychiatry and the law, depression, anxiety, dementia, and suicide risk and prevention.

Your father has developed paranoid delusions, and knowing how to respond to him is partly a matter of understanding what causes them. Delusions -- false, fixed beliefs -- are a common complication of dementia, particularly in the later stages. They're called "fixed" because no matter how good your argument is, no matter what proof you provide to show his belief is false, he can't be budged. You could have a private investigator follow your mother and film her every move to show there's no affair, or you could have the best accountants comb his finances to prove there's no wrongdoing, but it wouldn't help solve your problem.

Often the delusions in dementia are paranoid, as in your dad's case, because the delusion is in part an attempt to find something or someone to blame for why the person with dementia feels he has so little control of his life. Your father doesn't have the insight to recognize that it's his progressive dementia that's the source of his trouble. Instead, he presumes that his problem stems from someone betraying him.

The best strategy is to let your dad say what's on his mind and listen attentively. When he's done, let him know you're very sorry he feels this way, then try to gently change the subject. His belief is fixed, so trying to reason with him won't help. Agreeing with him, obviously, would open up a whole different set of potential problems.

Unfortunately, paranoid delusions can lead to aggression, so if gentle redirection isn't helpful, it's important to get professional help. A physician can evaluate him to be sure there's not a medication or a treatable medical condition triggering the delusions. If not, the doctor may broach the subject of considering an antipsychotic medication to treat the delusions.

Two important things to know about antipsychotics, though:

  1. They often decrease the intensity of delusions associated with dementia, but they aren't likely to eliminate them.
  2. The FDA has issued a severe warning about people with dementia taking antipsychotic medications. This is because there's an increased mortality risk for people with dementia who take them.

Be sure, therefore, to give careful consideration to the potential benefit such medication may provide in comparison to the potential risk.