Psychotic Risk Associated With Cannabinoid Use: A Case Report of Ekbom-Like Delusional Infestation

Abstract

Chronic use of high-potency cannabinoids has been consistently associated with an increased risk of psychosis, particularly with early onset, daily use and prolonged exposure. However, atypical somatic presentations may be underrecognised and can create diagnostic challenges in clinical practice. We reported the case of a 49-year-old man with long-standing daily cannabis use who developed delusional infestation characterised by persistent pruritus, tactile hallucinations and a fixed somatic delusional belief. Dermatological and neurological assessments, routine laboratory investigations, and cranial computed tomography did not reveal abnormalities suggestive of an organic aetiology. Mental status examination demonstrated a well-structured somatic delusion with absent insight. Treatment with olanzapine and psychoeducation was initiated, with gradual symptomatic improvement. This case report aimed to describe an Ekbom-like somatic presentation within a probable cannabis-induced psychotic disorder and to highlight the diagnostic value of structured clinical assessment, laboratory testing and normal neuroimaging findings in excluding secondary causes. This case underscores the need to consider substance-induced psychosis in patients presenting with delusional infestation, and it reinforces the importance of early recognition, careful differential diagnosis and counselling toward substance cessation to improve prognosis.