Meeting abstract

https://doi.org/10.24869/spsih.2026.342

From Collateral History to a Diagnosis of Induced Psychosis

Alen Mančić ; Clinical Hospital Centre Rijeka, Krešimira 42, 51000 Rijeka, Croatia; Faculty of Medicine in Rijeka, University of Rijeka, Braće Branchetta 20, 51000 Rijeka, Croatia *
Ena Žderić ; Clinical Hospital Centre Rijeka, Krešimira 42, 51000 Rijeka, Croatia; Faculty of Medicine in Rijeka, University of Rijeka, Braće Branchetta 20, 51000 Rijeka, Croatia
Gordana Rubeša ; Clinical Hospital Centre Rijeka, Krešimira 42, 51000 Rijeka, Croatia; Faculty of Medicine in Rijeka, University of Rijeka, Braće Branchetta 20, 51000 Rijeka, Croatia
Marina Letica Crepulja ; Clinical Hospital Centre Rijeka, Krešimira 42, 51000 Rijeka, Croatia; Faculty of Medicine in Rijeka, University of Rijeka, Braće Branchetta 20, 51000 Rijeka, Croatia
Tanja Grahovac Juretić ; Clinical Hospital Centre Rijeka, Krešimira 42, 51000 Rijeka, Croatia; Faculty of Medicine in Rijeka, University of Rijeka, Braće Branchetta 20, 51000 Rijeka, Croatia

* Corresponding author.

Abstract

Objective: To present the importance of collateral
history in the diagnostic process of psychotic
disorders by describing a patient in whom the
interview with a family member directed clinical
thinking toward a possible induced psychosis.
Materials and methods: Case report of a patient
hospitalized for the first time due to paranoid delusional
ideas. At admission, he reported a yearslong
conviction that he was exposed to cyberattacks,
surveillance, and control via artificial intelligence,
and that unknown persons had hacked
his mobile device with the aim of stealing data
and property, all of which he linked to his war experience.
He attributed part of his somatic complaints
to the actions of the same perpetrators.
During hospitalization, a psychiatric workup, psychological
testing, and a collateral interview with
his wife were performed. Statistical analysis: Not
applicable. Results: At admission, a working diagnosis of persistent delusional disorder was made.
His mental status was dominated by systematically
elaborated paranoid delusions, with preserved
orientation, formally coherent thought, and absence
of hallucinations. Psychological testing,
despite dissimulation, revealed pronounced paranoid
content, an elevated psychoticism index, and
poor insight. Collateral history from his wife revealed
that she claimed to have herself witnessed
the described events and stated that doctors
“cannot understand” the situation because only
military doctors can understand it. These findings
raised suspicion of an induced delusional disorder
(folie à deux). During two weeks of hospitalization,
with antipsychotic treatment, there was a
withdrawal of spontaneous psychotic production
and normalization of behavior, but insight into
illness remained markedly reduced, and the patient
and his wife continued to deny the existence
of a mental disorder. After discharge, the patient
did not attend the recommended follow‑up appointments.
Conclusion: This report highlights
the key role of collateral history in psychiatric
diagnostics. The information that a close person
shares and maintains the patient’s delusional beliefs
raised suspicion of an induced delusional disorder
(folie à deux), which significantly influenced
the diagnostic reasoning. The case underscores
the importance of systematically collecting information
from family members, as well as critically
assessing their credibility, especially when they
share and support the patient’s delusional beliefs.

Keywords

induced psychosis; collateral history; folie à deux

Hrčak ID:

353111

URI

https://hrcak.srce.hr/353111

Publication date:

15.6.2026.

Article data in other languages: croatian

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