Known collectively as the Z drugs, zopiclone (a cousin of Lunesta), zolpidem (Ambien) and zaleplon (Sonata) have been touted as the non-addictive alternatives to their benzodiazepine predecessors.
Nevertheless, a substantial and growing body of evidence suggests otherwise. Both human and animal studies into the abuse potential of zaleplon, for example, have found that dependence on this drug is similar to that of the benzodiazepine triazolam (Psychopharmacology [Berl], 1999; 145: 39-51; Drug Alcohol Depend, 2000; 61: 69-84).
The reported symptoms of non-benzodiazepine dependence include altered consciousness and visual hallucinations (Eur Psychiatry, 1999; 14: 358-9), psychomotor agitation, abdominal pain and hypertension (Dtsch Med Wochenschr, 2001; 126: 653-4).
While those who have a history of drug addiction or abusive personalities seem likely to abuse these drugs (Encephale, 2004; 30: 153-5), there have also been reports of patients with non-abusive tendencies who have developed a dependence on them (Actas Esp Psiquiatr, 2002; 30: 259-62; Rev Neurol, 2002; 34: 253-6; BMJ, 1998; 316: 117). People with psychiatric disorders are also more vulnerable to such addiction (Nervenarzt, 1999; 70: 72-5).
In addition, a number of these patients have reported feelings of euphoria and physical wellbeing, which may go some way towards explaining the addictive potential of the drugs (Encephale, 1999; 25: 652-7).
Patients believed to be dependent on the Z drugs typically display signs of withdrawal, including heightened levels of anxiety and craving (Int Pharmacopsychiatry, 1982; 17 [Suppl 2]: 228-34; BMJ, 1998; 316: 117). Other effects noted in patients in withdrawal are epileptic fits (Pharmacopsychiatry, 1991; 24: 138-40), sweating, palpitations, hot flushes, tremors and rebound insomnia (BMJ, 1998; 316: 117).
Given the evidence mounting against the drug companies' claims that the new-generation sleeping pills such as Lunesta are "non-narcotic", it's worth asking whether catching a few Zs is actually worth the risk of taking these Zs.