The neuropsychiatric sequelae of mercury poisoning. The Mad Hatter's disease revisited

Br J Psychiatry. 1995 Jul;167(1):95-8. doi: 10.1192/bjp.167.1.95.


Background: The detailed effects of mercury poisoning on cognitive function, brain anatomy and regional brain function are largely unknown. We report the case of a 38-year-old man who was exposed to toxic levels of inorganic mercury.

Method: Four years after exposure, the patient was assessed using magnetic resonance imaging (MRI), single-photon emission computerised tomography (SPECT) and detailed neuropsychological evaluation.

Results: The patient developed a myriad of physical and psychiatric complaints, including stomatitis, muscle spasm, tremor, skin rash and the psychiatric syndrome known as 'erythism' (Mad Hatter's disease). Neuropsychological evaluation revealed marked and significant deficits of attention concentration, particularly when under time pressure. The MRI scan was unremarkable; however, SPECT revealed hypermetabolism of the posterior cingulate

Conclusions: Mercury poisoning appeared to result in a dysregulation of posterior cingulate cortex, which was associated with attention/concentration deficits and marked anxiety/agitation.

Publication types

  • Case Reports

MeSH terms

  • Adult
  • Attention / drug effects
  • Brain / drug effects
  • Brain / pathology
  • Energy Metabolism / drug effects
  • Fungicides, Industrial / poisoning
  • Gyrus Cinguli / drug effects
  • Gyrus Cinguli / pathology
  • Humans
  • Magnetic Resonance Imaging
  • Male
  • Mental Recall / drug effects
  • Mercury Poisoning / diagnosis
  • Mercury Poisoning / psychology*
  • Neurologic Examination / drug effects
  • Occupational Diseases / chemically induced*
  • Occupational Diseases / diagnosis
  • Occupational Diseases / psychology
  • Phenylmercury Compounds / poisoning
  • Substance-Related Disorders / diagnosis
  • Substance-Related Disorders / psychology*
  • Tomography, Emission-Computed, Single-Photon


  • Fungicides, Industrial
  • Phenylmercury Compounds