Shared delusion amidst COVID-19 pandemic in 23-year-old monozygotic twins

Background

Folie à deux, also known as shared psychotic disorder, is a rare psychiatric syndrome in which a psychotic symptom is transmitted from one individual to another who is usually in close proximity. We report a case of folie à deux in adult monozygotic female twins who presented to the emergency department with disturbed behavior amid the Coronavirus disease 2019 (COVID-19) lock down.

Case report

We present the case of 23-year-old monozygotic female twins, with no past medical or psychiatric history, who presented with a two-week history of irritability, sleeplessness, and hyperreligiosity. They were found to be sharing a similar delusional belief with a religious theme. Routine investigations and brain imaging were unrevealing. The primary case (Twin A) was diagnosed with brief psychotic disorder and started on an oral antipsychotic. The secondary case (Twin B) showed gradual resolution of symptoms after separation from twin A.

Conclusion

This case highlights the complex interplay between genetic and environmental factors in the etiology of delusional symptoms in monozygotic twins.