Nearly twice as many people are taking heroin in former coalfield areas than elsewhere in Wales, research has shown.
A new substance misuse strategy is due to begin in May next year
The study reveals 2.8 people per thousand in the valleys had asked for treatment for heroin use compared with 1.5 per thousand in the rest of Wales.
Plaid AM Leanne Wood, who commissioned the research, wants a review of problem drug and alcohol users' services.
Ministers said spending on substance misuse had risen by 660% in five years and a new strategy was being developed.
But Ms Wood, a former probation officer, warned that existing services were "not dealing with this worsening problem".
The research, conducted by the assembly parliamentary service, covers the period between April 2005 and December 2006.
Former coalfield communities are defined as Blaenau Gwent, Bridgend, Caerphilly, Merthyr Tydfil, Neath Port Talbot, Newport, Rhondda Cynon Taff, Swansea and Torfaen.
Ms Wood has written to social justice minister Dr Brian Gibbons to ask for an investigation of services available for addicts.
"This research shows that people who live in the former coalfields of Wales continue to suffer the effects of the pit closure programmes," she said.
"Not only does this problem affect the lives of those who use heroin, it also affects the lives of all those who live in these communities.
"They suffer from high property crime levels associated with high levels of heroin use," she added."
Ms Wood said she was "encouraged" by the Labour-Plaid assembly government's approach to tackling drugs.
But she warned that there was a "long way to go" before former coalfield areas could "shake off the damaging effects of previous economic neglect".
A Welsh Assembly Government spokesperson said it recognised the importance of tackling all forms of substance misuses.
A statement said ministers had "acknowledged this through the significant additional investment made to increase access and availability to treatment services in Wales.
"In 2007/08 the substance misuse action fund stands at £22m. This substantial increase of 660% since 2002/03 has created over 9,300 treatment places since 2004.
"The Welsh Assembly Government is in the process of developing a new substance misuse strategy for Wales to replace the current strategy from May 2008," the statement concluded.