Criminality in patients with autoimmune encephalitis

Key points:

• Study links autoimmune encephalitis to delayed criminal behaviour.
• Treated patients showed lasting behavioural changes despite reduced antibodies.
• Delayed treatment may cause permanent brain changes in patients.

Introduction

Although patients with autoimmune encephalitis respond to immunotherapy, many exhibit neurobehavioural features.

A 2024 retrospective study examined five cases of criminal behaviour among autoimmune encephalitis (AE) patients seen at the Oxford Autoimmune Neurology Clinic between 2014 and 2021.

The behaviours included viewing child pornography (three cases), shoplifting (one case), and conspiracy to commit murder (one case).

The patients

All five patients were males in their 40s-60s with no prior criminal history or psychiatric disorders. Three had LGI1-antibody encephalitis, one had CASPR2-antibody encephalitis, and one was seronegative (no antibodies detected).

During acute AE, patients exhibited typical symptoms such as amnesia, behavioural disturbances, and insomnia.

Criminal behaviours emerged 15 months to 12 years after symptom onset. At the time of behaviours, none were receiving immunotherapies, and two were on neurotropic medications.

Two patients displayed new psychiatric features around the time of their crimes, such as euphoria, irritability, and obsessive-compulsive behaviours.

Long-term issues

When following up after 5-13 years, patients showed good functional outcomes but persistent behavioural issues including low mood, insomnia, agitation, and irritability.

Despite improved cognitive function and reduced autoantibodies, these residual symptoms persisted.

The criminal behaviours had severe legal and social consequences.

Conclusions

The researchers, which includes Encephalitis International’s CEO Ava Easton, propose that criminal behaviours may be a rare (1.7%) postencephalitic phenomenon that is due not to relapse of the disease, but because the brain’s emotional and behavioural control centres can be permanently changed by the original illness.

The team suggests that delayed administration of immunotherapy (more than 30 days after onset of disease) may contribute to residual neurocognitive syndromes. However, the researchers also urge caution in attributing criminality to AE, noting the possibility that a small percentage of the general population of older men without brain conditions may naturally commit crimes anyway.

 

Reference:

Michael, Sophia et al. “Criminality in patients with autoimmune encephalitis: A case series.” European journal of neurology vol. 31,4 (2024): e16197. doi:10.1111/ene.16197.