Misusing illegal drugs can have a number of negative affects, both on drug users themselves and on their families. Jobs may be lost, relationships with families and friends jeopardized, children neglected or abused and time spent in prison. Illegal drug users can also experience a variety of health problems as a direct consequence of their drug use but there has been little research into the health benefits of drug treatment in the UK. A study of 566 drug addicts in Scotland inteviewed them as they started their treatment and again after 8, 16 and 33 months. The study found that decreases in people's use of illegal drugs, or their dependence on them, was associated with significant improvements in physical and psychological health and in reductions in attendance at A&E departments.
Mcintosh, J., Bloor, M. and Robertson, M. - The health benefits of reductions in individuals' use of illegal drugs Journal of Substance Use August 2008, 13(4), 247-254