Glioblastoma and new-onset criminal behaviors in a geriatric patient: a forensic-psychiatric case report from Switzerland.

Organic brain disorders (OBD), including rapid-growth cancerous tumors, can have significant neuropsychiatric effects and in some circumstances have led to the manifestation of deviant behaviors that conflict with societal norms. This report describes the case of a geriatric male patient in Switzerland with no prior history of delinquency who in later life repeatedly committed stalking offences and aggressive acts. An initial forensic-psychiatric evaluation diagnosed this individual with persistent delusional disorder based on pronounced symptoms and rigid personality traits; during this assessment, the patient refused neuroimaging scans but later consented to these examinations. Thereafter, these revealed an isocitrate dehydrogenase wild-type glioblastoma and provided critical insights into his behavioral changes. Specifically, the tumor's location in regions of the brain responsible for executive functioning, emotional regulation, and social cognition likely contributed to the development of delusions and psychosis-like symptoms that ultimately resulted in new-onset delinquency. Thus, this case highlights the multifaceted challenges of OBDs in forensic-psychiatric contexts, accentuating a need for greater awareness and sensitivity towards these conditions, particularly when externalized deviant behaviors emerge in elderly groups that diverge from established patterns.