Delusion of Infidelity
A delusion of infidelity is the fixed, false belief that one's spouse or partner is being unfaithful. Despite being commonly referred to as a 'delusion of jealousy', this is somewhat of a misnomer: what the person actually experiences is morbid jealousy accompanied by a delusional belief in infidelity, rather than jealousy itself being the delusional content.
This has traditionally been noted to often develop gradually on a background of a person who was already somewhat suspicious, sensitive, or mildly jealous before becoming unwell, with the pre-existing personality trait slowly intensifying to delusional proportions rather than appearing abruptly out of nowhere.
Recognition features
- A fixed, unshakeable belief that a spouse or partner is being sexually unfaithful
- Often develops gradually on a background of pre-existing suspiciousness or mild jealousy
- The person may search for and misinterpret ordinary occurrences (such as marks on clothing or changes in a partner's appearance) as 'evidence'
- May fluctuate in intensity over time, with periods of intense interrogation or surveillance of the partner
Eliciting it at interview
- Ask directly and specifically about beliefs concerning a partner's faithfulness, and about what evidence the person feels supports the belief
- Assess safety carefully and explicitly, since this particular delusion carries a well-documented association with violence toward the partner and should never be treated as a purely private or low-risk matter
- Explore the history and premorbid personality, since a longstanding pattern of jealousy or suspiciousness preceding the current belief is a recognised and relevant feature
Distinguishing features
- Differs from ordinary jealousy in the fixed, unshakeable, and often escalating quality of the belief, and in the misinterpretation of neutral evidence as confirmatory
- Can occur in both functional and organic conditions, and is particularly associated with alcohol dependence among organic causes
- Frequently occurs largely in isolation, without the other symptoms that would suggest a broader psychotic illness such as schizophrenia
Common misconceptions
- That this is best described as a 'delusion of jealousy'; strictly, the jealousy is the emotional response, while infidelity is the delusional content
- That the risk associated with this delusion is overstated; it carries a genuinely elevated and well-recognised risk of violence toward the partner and should always be assessed with this in mind
Related phenomena
Practice this
A man with a long history of alcohol dependence becomes convinced his wife is having an affair, searching her clothing daily for "evidence" and reinterpreting entirely ordinary events (a late bus, a changed hairstyle) as confirmation. No amount of reassurance changes his conviction. What is this best described as? · A man with a long history of heavy alcohol use tells you he is certain his partner is having an affair, describing in detail how he has begun checking her phone daily and timing her return from work to the minute. He becomes agitated and mentions that he "won't let this go on." Before revealing the answer: what should this specific detail about his agitation and intent prompt you to assess directly? · A man becomes convinced that his neighbours are conspiring against him, monitoring his movements, and have poisoned his water supply. Separately, he has also become convinced his wife is secretly meeting other men, based on the same generalised sense of being watched. Which delusion is the water-supply belief? · A man has, for as long as his wife can remember, been generally suspicious of colleagues, neighbours, and now increasingly of her — but recently this has crystallised into an absolutely fixed, unshakeable conviction, unaltered by any reassurance or evidence, that she is having a specific ongoing affair with a named colleague. Is the fixed belief about the affair itself best understood simply as part of his paranoid personality disorder? · You suspect a patient may hold a delusion of infidelity about their partner. Beyond confirming the belief itself, which single additional question is most important to ask given the known risks associated with this delusion? · A man reinterprets his partner's ordinary late bus home as "proof" of an affair, despite this being explained and verified. Why is careful documentation of this delusion's content important beyond simply recording it as "jealousy"?
Illustration
A 55-year-old man with a long history of heavy drinking becomes convinced that his wife of thirty years is having an affair, citing as proof the fact that she occasionally comes home a few minutes later than expected from the shops, and has taken to searching her belongings nightly and questioning her for hours about her whereabouts, despite her repeated, consistent denials.
References
- Casey, P. & Kelly, B. (2019). Fish's Clinical Psychopathology, 4th ed. Ch. 4, 'Disorders of Thought and Speech'.