Morinan and Keaney Journal of Medical Case Reports 2010, 4:403 http://www.jmedicalcasereports.com/content/4/1/403 producing dependence compared to benzodiazepine hypnotics like temazepam. This was the conclusion reached by Hayak et al. [10] on the basis of the number of global prescriptions and a systematic Medline search covering a seven-year period up to 2002. However, the authors cautioned against their uncritical use in patients with a history of substance misuse and/or psychiatric ill- ness. A similar note of caution was sounded by Cimolai [14] who identified 20 cases of dependence on zopiclone (dose range 7.5 to 390 mg/d) in Canada between 1991 and 2006. Dependence on alcohol may co-exist with dependence on prescribed psychotropic drugs, thus complicating clinical treatment. Johansson et al. [15] collected data from a sample of alcohol dependents in both commu- nity (n = 130) and inpatient (n = 23) settings in Sweden. Seven percent of the outpatients and 13% of the inpati- ents were found to be dependent on zopiclone or zolpi- dem compared to 12% and 30% respectively for benzodiazepines. However, the severity of dependence as measured relative to the defined daily dose (DDD for zopiclone = 7.5 mg, zolpidem = 10 mg) was between 1.0 and 1.5 (range of mean values for the two Z-drugs in the two treatment settings) whereas for the benzodiaze- pines, the values were 5.5 for outpatients and 11.5 for inpatients; a value of ≥4.0 being considered high dose dependence (HDD). Using these values, our patient would be defined as HDD with a value of 12. In other case studies on zopi- clone dependence, ranges of 2 to 40 [9] and 1 to 51 [10] have been noted. In one case described as ultrahigh dose dependence, a 34-year old woman was taking zol- pidem equivalent to 200 and when abruptly discontinu- ing the drug, suffered withdrawal seizures [16]. In the Dublin sample, the mean age of onset and duration of zopiclone use was 28 and 4.2 years respec- tively with the mean age of the cohort being 32 years [9]. From the review of the 22 cases of zopiclone dependence, where the individual ages were presented (n = 15), the mean age was 39 years [10]. Our patient was 31 years old and although there are a few case reports of zopiclone being taken at doses higher than her typical daily intake of 60 mg, the 13 years of almost continuous use might be considered particularly unusual. It is also interesting to note that she had every intention of returning to zopiclone as soon as possible after discharge and that her experience with benzodiazepines was considered inferior to zopiclone. Comorbidity of alcohol dependence and anorexia ner- vosa is common and a serotonergic neuronal dysfunc- tion has been implicated in both disorders [17]. In our patient, her cravings for zopiclone following withdra- wal and interim substitution with diazepam would be indicative of dependence. We would recommend a Page 3 of 4 cautious approach to prescribing Z-drugs to patients with a dual diagnosis and that particular attention be paid to any request for an increase in the daily dose. Conclusion We have described an individual with an atypically long history of high dose dependence on zopiclone, alcohol dependence and anorexia nervosa. This case adds further support to the growing body of evidence that prescribing zopiclone to drug users with an underlying psychiatric disorder should be carefully monitored. Patient’s perspective Gratefully I’m still off zopiclone though I am aware I could get hold of it easily. As yet, there’s no detox for coming off zopiclone. No help provided for the mental or physical reasons and withdrawal. Consent Written informed consent was obtained from the patient for publication of this case report. A copy of the written consent is available for review by the Editor-in-Chief of this journal. Authors’ contributions FK is the Consultant Psychiatrist on the AAU and AM is a Research Scientist (Pharmacology). AM interviewed the patient and wrote the manuscript. Both authors read and approved the final manuscript. Competing interests The authors declare that they have no competing interests. Received: 9 March 2010 Accepted: 10 December 2010 Published: 10 December 2010 References 1. Wilson S, Nutt D: Management of insomnia: treatments and mechanisms. Br J Psychiat 2007, 191:95-197. 2. Sanger D: The pharmacology and mechanisms of action of new generation, non-benzodiazepine hypnotic agents. CNS Drugs 2004, 18:9-15. 3. Ebert B, Wafford KA: Benzodiazepine receptor agonists and insomnia: Is subtype selectivity lost in translation? Drug Discovery Today 2007, 3:547-554. 4. Leonard BE: An introduction to enantiomers in psychopharmacology. Hum Psychopharmacol 2001, 16:s79-s84. 5. 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