Factitious disorder is the deliberate feigning or induction of illness in order to adopt the sick role, without an external incentive. Self-administration of insulin, evidenced by high insulin with suppressed C-peptide, is a classic method. The extreme form, Munchausen syndrome, adds pseudologia fantastica with elaborate dramatic accounts, peregrination between hospitals and cities, and repeated submission to invasive procedures such as laparotomy. The absence of any financial or legal incentive is what separates it from malingering.
The chapter distinguishes four concepts along two dimensions: whether the symptom is deliberately produced, and what the motivation is. Functional disorders involve symptoms that are genuinely experienced and not deliberately produced. Factitious disorder involves deliberate production for internal reward, namely the sick role. Malingering involves deliberate production for external reward such as money, drugs or avoidance of duty, and is not a psychiatric diagnosis. Illness anxiety disorder concerns preoccupation with having a disease in the relative absence of symptoms, and somatic symptom disorder concerns distress and disproportionate thoughts and behaviours about real symptoms.
This terminology is examined every year and is expected of every resident, placing the item at the Core level of RITE content. Remember that these categories are not mutually exclusive over time and that establishing deliberate production requires objective evidence, such as the biochemical mismatch and the discovered syringes in this case.
Incorrect Answers
- B. Functional neurological symptom disorder involves genuinely experienced symptoms with positive incongruity signs and no deliberate production or objective evidence of deception.
- C. Malingering requires an identifiable external incentive such as financial gain, drugs or avoidance of duty, which is absent here.
- D. Illness anxiety disorder involves preoccupation with the fear of having a disease with few or no somatic symptoms, and no self-induced pathology.
- E. Somatic symptom disorder involves distressing real symptoms with disproportionate thoughts, feelings and behaviours, without deliberate induction of illness.
Testing Pearls
- Factitious disorder is deliberate production of illness for the internal reward of the sick role.
- Munchausen syndrome adds pseudologia fantastica, peregrination and repeated invasive procedures.
- High insulin with suppressed C-peptide indicates exogenous insulin administration.
- Malingering requires an external incentive and is not a psychiatric diagnosis.
- Functional disorder symptoms are genuinely experienced and not deliberately produced.
References
- Jankovic J, Mazziotta JC, Newman NJ, Pomeroy SL, editors. Bradley and Daroff's Neurology in Clinical Practice. 8th ed. Philadelphia, PA: Elsevier; 2022. p. 2077.
- Bass C, Halligan P. Factitious disorders and malingering: challenges for clinical assessment and management. Lancet. 2014;383(9926):1422-1432.
- Stone J, Smyth R, Carson A, Lewis S, Prescott R, Warlow C, et al. Systematic review of misdiagnosis of conversion symptoms and "hysteria". BMJ. 2005;331(7523):989.
