The largest ever study of heroin and crack cocaine treatment programmes in England has shown that the first six months of treatment leads to large proportions of addicts of one drug or the other abstaining.

The findings from the National Treatment Agency for Substance Misuse (NTA) funded study are reported in an article written by Dr John Marsden, Institute of Psychiatry, King's College, and Colin Bradbury, NTA, and colleagues which will be published online today (2nd October) (www.thelancet.com) and in an upcoming edition of The Lancet.

The authors used data from the National Drug Treatment Monitoring System (NDTMS) to prepare their analysis. The study involved more than 14,656 patients across England, with a heroin or crack cocaine addiction, or both. Patients were treated between January and November 2008, received at least 6 months' treatment or were discharged by the study endpoint (May 2009).

The study found that, during the 28 days before review, around two thirds of heroin users stopped or substantially reduced their use of heroin (42% stopping, 29% reducing); a similar proportion of crack cocaine users had stopped or substantially reduced their use of crack cocaine (57% stopping, 8% reducing). A higher proportion of users of heroin only abstained than did users of both heroin and crack cocaine (42% vs. 33%), and more users of crack cocaine only abstained than did users of both drugs (57% vs. 51%). Overall heroin use reduced by a mean average of 15 days per month (from 23 days per month pre-treatment to eight days at follow-up) and crack cocaine use by eight days per month (from 13 days per month pre-treatment to five days at follow-up). For clients given drug treatment, reduction in days of heroin use was smaller for users of both heroin and crack cocaine than for users of heroin alone (14 vs.16 days).Colin Bradbury, Head of Delivery, NTA said: "Drug treatment has been greatly expanded in the last few years and so it is very encouraging that this study of the most commonly available treatments in England shows that even those with entrenched addiction to heroin and crack cocaine respond well to treatment. Whilst users are in treatment, we know that their drug use declines and that crime significantly reduces, which is positive for their health and for communities which suffer from the harms caused by drug addiction.

"The goal of all drug treatment is for the user to overcome their addiction, and this study shows that although that may take time, it is possible to tackle the harms caused by drugs by investing in drug treatment."