Delusions may persist or be short term

DEAR DOCTOR K: I hear the phrase “you’re delusional” used so casually. But what does it mean when someone is really, clinically delusional?

DEAR READER:

A delusion is a false belief that is based on an incorrect interpretation of reality. A person with delusional disorder will firmly hold on to a false belief despite clear evidence to the contrary.

Delusions can be caused by mental illnesses called psychoses. These include schizophrenia and bipolar disorder. Delusions also can occur in degenerative brain conditions, particularly Alzheimer’s disease.

Delusions often are beliefs that could not possibly be true. If I believed that I were Joan of Arc, or that the moon was going to smash into the Earth tomorrow, those would be delusions.

Delusions also can be about something that is not happening but that could occur in reality. The CIA could really be tapping my telephone, for example: I have a phone, and the CIA has the ability to tap it. If I devoutly believed that the CIA was tapping my phone, yet couldn’t give you a plausible explanation for why it would want to do that, I would likely be delusional.

In a condition called delusional disorder, a person with otherwise normal thinking continues to hold one very focused delusion.

In some with delusional disorder, the delusion may continue for years, though it may vary in its intensity and significance. In other people, the disorder lasts only a few months.

Anyone expressing delusions has an serious underlying mental or neurological disorder. Medications and psychotherapy can help. The hardest part is getting someone who is delusional to recognize that he or she may need help.