Zopiclone: is there any dependence and abuse potential?

Both published and unpublished data concerning the rebound, withdrawal, dependence and abuse potential of zopiclone have been reviewed. As expected for an hypnotic drug of about 5 h elimination half-life, rebound has occasionally been detected but is substantially less frequent than with equivalent benzodiazepines. Tolerance to zopiclone does not occur regularly and cross-tolerance to the benzodiazepines may help in a regimen to withdraw from the latter drugs. Dependence on long-term use, as shown by either a characteristic withdrawal syndrome or by psychological craving, is rare considering the world-wide extent of usage. Abuse (addictive non-medical use) is documented but is also rare, in comparison with the widely abused benzodiazepines. It is concluded that zopiclone has substantial advantages over the benzodiazepines in terms of dependence and abuse potential.