I think it is important to note that not all sedative/hypnotics are created equal. Diazepam is almost impossible to fatally OD on unless one has taken other CNS depressants. Nitrazepam, Flunitrazepam, Clonazepam & Nimetazepam (the nitrobenzodiazepines) can be fatal in large doses. Studies in Nordic countries identified this fact only 2 or 3 years ago. As for other benzos, especially those sold as RCs, nobody knows. Barbiturates and related drugs (e.g. phenobarbitone) are VERY dangerous in overdose. Clomethiazole (Heminevrin) is similarly dangerous. Not enough research has been carried out on the 'Z drugs' but overall, almost all sedative hypnotics carry a risk. As well as the risk of OD, people under the influence may end up doing things that they would never contemplate when sober.
I guess most people here aren't old enough to remember when barbs were popular but let me tell you, people ended up in a terrible mess and suddenly stopping using ANY sedative/hypnotic after long-term use can have very serious effects. I speak as someone who went from 12mg of clonazepam a day to nothing. I lost 3 weeks and woke up in hospital. In retrospect, I'm lucky to have lived.
