Funding cuts and reforms to public services risk reversing the declining trend in drug abuse among young people, campaigners have warned.
NHS reforms, the introduction of police and crime commissioners and the growing use of payment by results could lead to services for young people increasingly having to compete for funding with adult care budgets, the report by the UK Drug Policy Commission (UKDPC), DrugScope and Mentor said.
"It may appear trite to talk about young people as 'the nation's future' or to raise the spectre of 'a lost generation' but it is nevertheless essential for society to ensure that we provide an environment that supports the healthy development of young people," it said.
"Our study suggests that at present this may be under threat and we run the risk of reversing the welcome declining trend in substance misuse among young people. This will have a negative impact on families, schools, neighbourhoods and communities, as well as young people themselves."
Many health and well-being boards, which will set the strategic direction for public health, may have an "adult bias", the study said.
"A key risk is the lack of young people-specific outcomes in the public health outcomes framework and the potential domination of adult agendas on health and wellbeing boards," the report said.
Nicola Singleton, the UKDPC's director of policy and research, said: "Drug use among young people has fallen sharply over the last decade at the same time as we saw a sustained investment in young people's services. That investment helped create joined-up services that allowed early intervention before specialist drug services were needed. Now these services are threatened by a combination of financial pressure and the speed and scale of the current public-service reforms."
Dr Marcus Roberts, director of policy and membership at DrugScope, added: "Unfortunately, we've been hearing concerns from DrugScope's member agencies for some time now about the impact of local spending cuts and structural reforms on young people's drug and alcohol treatment.
"This report provides evidence that significant changes in the way that services are planned and commissioned, coupled with severe budgetary pressures, are threatening to undo the progress that has been made in treatment for this group over the past decade."
A Government spokeswoman said: "As part of our drugs strategy, we want everyone, including young people, to get off and stay off drugs. From next year, local authorities will be given a ring-fenced public health budget to tackle local public health issues. This will offer real opportunities to integrate drug treatment and other local services in the community."