Problem drug use will never be tackled effectively unless efforts are made to overcome poverty, according to the Scottish Drugs Forum (SDF).
Mr Liddell said drugs like heroin numbed people from life's realities
David Liddell, director of the drugs charity, told a conference in Glasgow that drug problems were wrongly seen as a medical or criminal justice issue.
He said they should instead be regarded as a social problem and a symptom of a dysfunctional society.
The conference is being held to mark the 20th anniversary of the SDF.
Scotland has one of the highest levels of problem drug use in Europe, with an estimated 51,000 people with addictions.
Mr Liddell said: "It cannot be a coincidence that depressants, including heroin, remain the most favoured drugs of choice in Scotland.
"They numb some of the most vulnerable people in our society from the harsh realities and overwhelming difficulties of their lives - the very people least able to cope with such challenges.
"But current drugs strategy fails to focus on how to overcome these root issues, robbing problem users of vital opportunities which can help them avoid them developing a drug problem or finding a route out of it."
The Scottish Executive's latest investigation into drug-related deaths found 42% occurred within the most socially deprived areas of Scotland in 2003.
In Greater Glasgow, which has the largest number of drug deaths in the country, 58% of its deaths were in the "most deprived" category.
The SDF director made the call at a drugs conference in Glasgow
"We need to return to the thinking of 20 years ago when we looked upon problem drug use as primarily a social issue, which has medical or criminal justice implications," Mr Liddell told delegates.
"That will pose huge challenges for public policy in terms of its focus and spending choices, but it is strikingly clear that the status quo is not an option.
"We have got to stop going down the road of just seeing problem drug use as an individual's personal failing.
"We need to start asking questions about wider society's responsibilities for creating the structures which allow problem drug use to develop and flourish.
"By continuing to focus almost exclusively on the 'culpability' of problem drug users for society's wrongs, we let those who have the power to influence the way we live completely off the hook."