Aggression in epilepsy and sleep: from historical accounts to brain networks and human behaviour

For a long time, epilepsy has been associated with violent behaviour, acquiring a highly stigmatising reputation, shaped mainly by 19th-century medical theories that postulated a direct connection between epilepsy and the criminal personality. Such stigma exerts a negative effect on the quality of life of people with epilepsy and remains a significant concern in forensic settings. This narrative review aims to thoroughly explore the relationship between epilepsy and aggression, highlighting the misconceptions that contribute to this stigma. The evidence presented in this review draws on the authors' experience and a PubMed search conducted in December 2024. The manuscript is organized into five chapters, addressing: (1) the historical and cultural background of epilepsy and violence; (2) the clinical features of aggression as a peri-ictal manifestation; (3) the neural networks underlying aggression in epilepsy; (4) aggression in sleep-related disorders, an area closely related to epilepsy, where clinical interest and reports of sleep-related violent episodes have progressively increased in recent years; and finally, (5) forensic considerations. In total, 326 records were identified though PubMed search. Only papers relevant to the topics were included. Relevant publications were also added manually from the authors' own files. One hundred and thirty-two studies were ultimately included in this narrative review. The review, addressing the topic from a historical perspective, traces the evolution of stigma and the concept of the "epileptic personality", from early observations to contemporary understanding. Next, we explore aggression and violence as peri-ictal manifestations, examining both their clinical characteristics and the brain networks implicated in the generation of aggressive behaviours during seizures. We try to elucidate the neurobiological substrates underlying these manifestations using intracerebral recordings. We then turn to violence associated with parasomnias, analysing and comparing the mechanisms underlying aggression and violence occurring in epileptic seizures with those observed during sleep in parasomnias, integrating evidence from intracranial EEG studies of disorders of arousals. This comparison highlights key similarities, differences, and the risk of a misdiagnosis. Finally, we address the legal and forensic implications of seizure- and sleep-related aggression and violence. Epileptic seizures and parasomnias can cause injuries to the affected person or to those nearby, but they can rarely be truly classified as acts of violence. However, although aggressive behaviour is uncommon during seizures, it may lead to legal consequences. Despite efforts from scientific societies and patient organisations, the stigma toward epilepsy persists, requiring further action and a deeper scientific understanding of this subject.