High-dose zolpidem abuse in a patient with insomnia comorbid with major depressive disorder

A 39-year-old married woman was referred to a psychiatry outpatient clinic for treatment of major depressive disorder (MDD). The dose of zolpidem she had been taking had increased to more than 500 mg/day and, therefore, she was hospitalized with the aim of zolpidem detoxification. On admission, her serum zolpidem level was 1550 ng/mL, and this dropped to less than one (ng/mL) within 50 h. However, after discontinuation of zolpidem, she experienced withdrawal symptoms. Though a few cases of high-dose zolpidem abuse have been reported in Japan, physicians should be aware that zolpidem has the potential for abuse and dependence.