Factitious Disorder Imposed on Self aka FDIS (Munchausen Syndrome): A Contemporary Analysis of Aetiology, Presentation, and Management.

Abstract

Factitious Disorder Imposed on Self, FDIS, historically known as Munchausen Syndrome, is a rare, yet clinically profound, mental health condition characterised by the intentional fabrication or induction of physical or psychological symptoms in the absence of obvious external incentives. The core motivation is psychological, stemming from a compulsive need to assume the sick role. FDIS presents a formidable challenge to healthcare systems globally, consuming vast resources through unnecessary, high-risk investigations and treatments. Contemporary research has illuminated strong links between FDIS and early life trauma, severe personality pathology, notably Borderline Personality Disorder, BPD, and a propensity for medical peregrination. Effective management necessitates a coordinated, multidisciplinary strategy, prioritising a non-confrontational approach and long-term psychotherapeutic engagement to address the underlying emotional distress.

Introduction

Factitious Disorder Imposed on Self, FDIS, represents one of the most complex diagnoses encountered in modern medicine, fundamentally disrupting the fiduciary nature of the doctor-patient relationship. First described by British psychiatrist Richard Asher in 1951, the term Munchausen Syndrome was coined after Baron von Munchausen, an 18th-century German nobleman renowned for his extravagant and false tales of adventure (Asher, 1951). The disorder is currently classified in the Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition, Text Revision, DSM-5-TR, under the somatic symptom and related disorders (American Psychiatric Association, 2022).

The central defining feature of FDIS is the deliberate act of deception, falsification, exaggeration, or induction of illness, sustained by the internal psychological need to be perceived as sick or injured (Feldman, 2018). This internal gain clearly differentiates FDIS from malingering, where the motivation is strictly for external rewards, such as avoiding work or obtaining financial compensation (Folks, Feldman, & Ford, 2000). Whilst historically considered a condition predominantly affecting men, contemporary large-scale database studies indicate a significant prevalence amongst females, frequently those with a background in the healthcare profession (Martin et al., 2021; De La Rivière et al., 2023). Due to the deceptive nature of the behaviour and the phenomenon of medical peregrination, the migration between numerous healthcare facilities, its true prevalence remains uncertain, though estimates range from 0.02% to 3% in inpatient settings (Yates & Bass, 2016; Sharma & Verma, 2022).

Aetiology and Psychosocial Underpinnings

The aetiology of FDIS is considered multifactorial, lacking a single verified organic cause, but strongly rooted in developmental psychology and personality pathology.

Developmental and Trauma-Related Factors

A recurring theme in the psychosocial history of individuals with FDIS is a background of significant childhood adversity, including emotional neglect, physical abuse, or early loss (Caselli et al., 2019). Feigning illness is hypothesised to serve as a deeply maladaptive coping mechanism, replicating a scenario where the individual received intense, unconditional care or attention that was otherwise absent in their formative years (Feldman & Eisendrath, 2024; Grosdidier, Bense, & Faget-Agius, 2024). One review of dialogue from online support communities noted that the vast majority of members described various forms of childhood emotional or physical abuse, supporting the hypothesis that the sick role becomes an acquired identity providing a sense of comfort, security, or self-worth (Yates & Feldman, 2019). Furthermore, a history of major childhood illness, resulting in prolonged hospitalisation and medical attention, may condition the individual to associate the patient role with receiving comfort and security, thereby reinforcing the behaviour (Kanaan & Wessely, 2010).

Personality Pathology and Comorbidity

There is a significant and consistently reported comorbidity between FDIS and Personality Disorders, particularly Borderline Personality Disorder, BPD (Gnanadesigan & Stoudemire, 2012). BPD features, such as emotional dysregulation, an unstable self-image, and a profound fear of abandonment, align closely with FDIS behaviours (Feldman & Feldman, 1995). The dramatic presentation, the urgency of medical complaints, and the clingy demand for hospitalisation may function as a desperate, though destructive, attempt to stabilise a fragile identity or cope with overwhelming interpersonal stress (Nadeau & Malingering, 2024; Sharma & Verma, 2022). One retrospective study of FDIS cases found that a large proportion of patients exhibited a high rate of prescribed psychotropic medications, including antidepressants (58.3%) and anxiolytics (66%), reflecting the significant burden of co-occurring depression and anxiety alongside the factitious behaviour (Martin et al., 2021).

Clinical Presentations and Diagnostic Challenge

The presentation of FDIS is highly varied, limited only by the individual's imagination and medical knowledge. The sophistication of deception, termed pseudologia fantastica, often necessitates extensive investigation to confirm the factitious origin of symptoms.

Self-Induction and Harm

Patients may induce severe, unexplained anaemia, sometimes referred to as Lasthénie de Ferjol syndrome (Feldman, 2018). This is achieved via occult bloodletting, self-inflicted injuries, or the surreptitious ingestion of anticoagulants (Asher, 1951). A 2025 case report highlighted the complex ethical dilemma of involuntary admission for a patient with recurrent life-threatening iron-deficiency anaemia eventually attributed to FDIS (Eng, Neo, & Chang, 2025).

Factitious hypoglycaemia is a high-risk presentation where patients secretly self-inject insulin or ingest sulphonylurea medications (Lebowitz & Blumenthal, 1993). The critical diagnostic clue, often confirmed through endocrinology literature, is the laboratory finding of a low C-peptide level alongside high insulin or sulphonylurea levels, definitively proving the source is exogenous, non-self-produced (Wallach, 1994; BMJ Best Practice, 2023).

Individuals may also induce sepsis or localised infections by contaminating wounds or intravenous access lines with foreign or faecal matter, leading to infections by unusual or polymicrobial pathogens that fail to respond to standard care (Sutherland & Rodin, 1990).

Falsification and Exaggeration

FDIS comprises the falsification of psychological symptoms. A 2024 case study described the late detection of FDIS in a patient feigning schizophrenia, presenting with bizarre and fluctuating complaints, such as commanding hallucinations (Shamsudin et al., 2024). The symptoms were observed to resolve rapidly when the patient's requests, such as specific medications, were granted, and worsen when they were denied, providing an objective window into the feigned nature of the illness. Tampering with medical evidence, such as spoiling urine samples with blood or manipulating medical records, is a common deceptive tactic (Pachkin & Zito, 2023).

Diagnosis and Management Strategy

Diagnosis rests not on a single test, but on a pattern of behaviour and a systematic approach to excluding organic disease whilst objectively confirming the presence of deception (Mayo Clinic Staff, 2024). Key elements include exclusion of genuine illness, identification of deception through objective evidence, and confirmation that the behaviour is driven by internal psychological need rather than external gain (Thompson & Wilson, 2022; Mayou & Farmer, 2024).

Treatment is challenging and the prognosis is guarded. The primary organisational strategy involves a “Gatekeeper” Model, where a single physician coordinates all care (Feldman & Eisendrath, 2024). Psychotherapeutic intervention, particularly CBT, remains the primary modality (Yates & Feldman, 2019). The goal is to validate suffering without reinforcing deception, and to redirect focus toward trauma, identity disturbance, and coping skills. In life-threatening cases, involuntary psychiatric admission may be ethically justified under the Mental Health Act (Eng, Neo, & Chang, 2025).

Conclusion

Factitious Disorder Imposed on Self is a severe and often tragic psychological imperative rooted in a complex dynamic of developmental trauma, personality dysfunction, and a compulsive need to inhabit the sick role. Its deceptive nature places enormous diagnostic pressure on clinicians, consumes disproportionate healthcare resources, and subjects patients to significant iatrogenic risk. Effective management demands a high index of clinical suspicion, a rigorously coordinated medical strategy centred on a 'gatekeeper' system, and a persistent, non-judgmental psychotherapeutic commitment focused squarely on addressing the underlying emotional pathology.

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