Euphoric effect induced by zolpidem: a case study of magnetoencephalography

Initially, zolpidem, a non-benzodiazepine hypnotic agent, was considered to have fewer adverse reactions than traditional benzodiazepines. However, after zolpidem was approved for medical use, an increasing number of case reports have described abuse or dependence complications. We were especially interested in the cases of dependence that presented a paradoxical ‘euphoric’ effect of zolpidem. This article reports the case of a female zolpidem-dependent patient who presented with 6 years of daily use of 400–1400 mg of zolpidem. She reported subjective effects of euphoria, intense craving and the inability to stop drug ingestion. Her diagnoses were zolpidem dependence and a depressive episode induced by substance abuse. To explore the neural mechanisms of the euphoric effect caused by high-dose zolpidem, we performed repeated magnetoencephalography (MEG) recordings. Before undergoing detoxification, her MEG results indicated that cerebellar electrical signal activation increased when taking high zolpidem doses. However, the prefrontal and parietal lobes’ electrical signal activity showed a tendency to recover to a normal state as the withdrawal time progressed to completion. This case suggests that the cerebellum plays a role in the euphoria induced by high zolpidem doses and provides clues for further research.