The general principles of harm reduction remain the same whatever the substance or behavior involved; these are pragmatism, compassion, evidence-based practices, and support for any positive change. However, specific harm reduction strategies can vary depending on the nature of the drug or behavior involved. A good case in point is alcohol vs. opiates. It is almost a cardinal rule of opiate harm reduction to use with others and NOT to use alone. But some drinkers find that drinking alone is much safer and choose to abstain in public and only drink when at home. (Other drinkers choose to only drink in public and never at home as a strategy to reduce consumption). Is there any evidence to support the idea that drinking alone might be a good alcohol harm reduction strategy whereas using opiates alone is not? Yes there is.
Overdose is the number one cause of sudden death among opiate users. The CDC estimates that there were 39,000 drug overdose deaths in the United States in 2006--almost as many as there were deaths from automobile accidents and more than the number of e=deaths from firearms. Although the CDC did not specifically list information about non-overdose drug related deaths--it is clear from the above that drug related auto fatalities must be small in comparison to overdoses since there are almost as many overdoses as total auto fatalities.
By way of contrast, death from alcohol overdose is relatively rare. The CDC reported 75,766 sudden deaths due to alcohol in the year 2001. 331 (0.4%) were due to alcohol poisoning (i.e. overdose). 171 (0.2%) were due to aspirated vomit. By way of contrast, 13,674 (18%) were motor vehicle traffic injuries, 7655 (10%) were homicides, and 4766 (6%) were due to falls. Experience tells us that most cases of death by alcohol poisoning or aspirated vomit occur with neophyte drinkers, and we do NOT recommend that neophyte drinkers drink alone. However, it can be safer for some people to stay at home when they drink than to go out.
Associated Press. Drug deaths outpace car crashes in more states http://www.msnbc.msn.com/id/33091645/ns/health-addictions
CDC. Alcohol-Attributable Deaths and Years of Potential Life Lost --- United States, 2001 http://www.cdc.gov/mmwr/preview/mmwrhtml/mm5337a2.htm