McQuaid et al report that clinicians working in their injectable opiate clinic were cautiously supportive of the use of injectable opiates for reinforcement but more hesitant about the use of voucher- and prize-based contingency management procedures.

These perceptions mimic those of clinicians in the USA. Upon initial exposure to contingency management interventions, many clinicians express concerns ranging from hesitation to outright opposition. However, after observing the beneficial effects in practice great shifts in attitude occur. Some who were initially the greatest critics become the strongest supporters of contingency management once they see its benefits with particularly difficult clients.

As in the London programme, critics often evoke ‘ethics’ to dismiss contingency management. This denunciation is paradoxical, as reinforcement principles upon which contingency management interventions are based are operative in every facet of life. Furthermore, one must wonder about the ethics of withholding an efficacious intervention. It was not long ago that opiate substitution treatment, now considered one of the most effective prevention interventions for HIV transmission, was itself labelled unethical.