In this series, I dig a little deeper into the meaning of psychology-related terms. This week’s term is delusional disorder.
Delusional disorder falls within the DSM-5 group of psychotic disorders, which also includes schizophrenia and schizoaffective disorder. However, it’s different, in that its effects are much more compartmentalized.
In delusional disorder, the delusional beliefs are focused on one area of the individual’s life, and don’t really bleed over into other areas. The delusions are non-bizarre, meaning they’re at least somewhat within the realm of possibility (e.g. being harassed by the neighbours rather than having aliens come down to the chimney to implant listening devices in one’s stomach), but they are still delusional. Typically, hallucinations aren’t present, but if they are, they relate to the delusional themes.
Functioning is generally preserved in areas that aren’t directly related to the delusions. This means that other people might have no idea no idea that the individual was unwell if their interactions didn’t venture into the topic area related to the delusions.
Delusional disorder subtypes
There are several subtypes based on the nature of the delusions:
- erotomanic: delusions revolve around the belief that someone else is in love with them, and the delusional individual may end up stalking/harassing that person as a result
- grandiose: these beliefs about having special attributes or abilities are to the intensity and extent that they’re delusional
- jealous: these delusions tend to focus on the delusional individual’s partner being unfaithful, even when there’s no evidence to indicate that they are
- persecutory: paranoid beliefs about others harming them, which may lead to pursuing litigation or criminal charges against the person that’s believed to be responsible; this is the most common subtype
- somatic: these delusions relate to something being wrong with one’s body
It’s worth noting that while delusional disorder is subtyped based on the type of delusions it presents with, the delusions themselves can occur in any type of disorder with psychosis, including schizophrenia or mood disorders.
Delusional disorder typically arises well into adulthood, with the average onset at age 40. Sometimes it will develop in people who already have paranoid personality disorder. It’s less common than schizophrenia, occurring in only 0.1–0.2% of the population. It doesn’t tend to occur more in one sex than the other, although females are more likely to have the erotomanic subtype, while males are more likely to have jealous or persecutory delusions.
Psychological factors, including social isolation, envy, suspicion, and low self-esteem may contribute to people developing delusional explanations for their inability to cope. A number of potential biological factors have been identified, but nothing clear-cut has been established.
Some of the associated factors with delusional disorder(note: correlation does not equal causation) include being married, being employed, having recently immigrated, low socioeconomic status, being celibate (for men), and being widowed (for women).
Anosognosia (lack of insight) is typical with this condition, and can make treatment and establishing a therapeutic relationship difficult. The focus may be to prevent destructive behaviours related to the delusions. Antipsychotics may help, and sometimes mood stabilizers are used as an adjunctive treatment. However, delusional disorder tends to be much less responsive to medications than other psychotic conditions.
The prognosis is better for females, those whose illness begins before age 30, and those who have a sudden onset of symptoms.
I had a few patients with delusional disorder over the years, but the one I got to know best was my patient at a community mental health team. He had the persecutory subtype, and believed there was a group of people harassing him. While he had zero insight, he was very bright and cognitively intact. He accepted medication primarily because it helped with sleep, and he was willing to accept mental health support in relation to the stress he experienced secondary to the harassment. There would have been no hint of psychosis if the conversation didn’t venture into the area of this perceived harassment. Had we tried to work on insight with him, I’m quite sure that would have been the end of him agreeing to see us. It’s quite the fascinating disorder, although certainly not something that would easy to live with.
Is delusional disorder something you’ve ever heard of or encountered?
- Medscape: Delusional disorder
- Merck Manual Professional Version: Delusional disorder
- StatPearls: Delusional disorder
The Psychology Corner has an overview of terms covered in the What Is… series, along with a collection of scientifically validated psychological tests.