There is limited awareness of cannabinoid hyperemesis syndrome among psychiatrists and physicians, which results in diagnostic failure and inadequate treatment. In this article, Dr Rehman and colleagues discuss the successful management of such a case, including recognition of the condition, diagnostic measures, treatment and long‐term follow‐up.

Neurosyphilis can mimic many neurological and psychiatric disorders. Though several of its varied central nervous system manifestations can be measured clinically and by neuroimaging, they are non-specific. Thus, this mimicry and the relative rarity of the illness in the present era make the diagnosis elusive. However, neurosyphilis is readily treatable; therefore, it must be considered a diagnostic possibility in the routine workup of early-onset dementia. This case report is of a young man presenting with psychosis and cognitive impairment. His brain scan showed hippocampal atrophy, a finding not often seen in neurosyphilis but more common in Alzheimer’s disease. Without awareness of the various causes of mesiotemporal atrophy, clinicians may erroneously diagnose cases such as this one as a neurodegenerative disorder.