Background
Several randomised controlled trials (RCTs) show that supervised heroin assisted treatment (HAT) is effective for people with long-term heroin addictions for whom the standard opioid substitution treatments (OST), such as methadone maintenance treatment (MMT), have not worked. Little is currently known about why and how HAT works.
Objectives
This paper reports on three inter-related studies undertaken by the author to assess what works for whom, in what circumstances and why in HAT.
Methods
The first study is a recently published systematic review and meta-analyses analysing the effectiveness of supervised HAT. The second study is a small-scale evaluation of a HAT programme in the UK. The third study is a living, realist synthesis of HAT.
Results
The systematic review concluded that when compared to MMT, supervised HAT more consistently retains people in treatment and reduces their consumption of illicit drugs. This finding is re-affirmed in the evaluation. Missing from both these studies is a detailed understanding of the mechanisms of action in HAT. Consequently, the third study presents some emerging findings from a living realist synthesis to understand the generative mechanism(s) of HAT focusing on the key realist question of what works, for whom, in what circumstances.
Implications
The paper concludes that HAT is by its nature a complex intervention, but one that should be re-invigorated as part of the repertoire of options and policy makers disposal to address record and rising levels of drug-related mortality in the UK and elsewhere.