The poll published today – the first of its kind carried out among politicians north of the Border – revealed that just 35% of MSPs think policies on illegal drugs are effective.
Just over half – 57% – agreed that the topic is so controversial it can be difficult to have an objective debate about the issue.
While most MSPs surveyed – 70% – thought policies should make more use of evidence and research, they were largely not in favour of exploring the possibility of making radical changes to drug policy.
Only about one-quarter – 27% – agreed consideration should be given to no longer making the possession of small quantities of drugs for personal use a criminal offence, with 51% against this idea.
The survey, carried out by the UK Drug Policy Commission (UKDPC), an independent body which aims to objectively analyse drug policies, was based on the anonymous opinions of 55 out of 129 MSPs and weighted to reflect the political composition of Holyrood.
It also found that 68% of the MSPs agreed Scotland should have more powers over policy about illegal drugs, including control laws, compared to 26% who did not.
The poll was carried out before the publication of figures last month which showed drug-related deaths have reached a record level in Scotland.
Last year there were 584 north of the border, the highest ever recorded and up 20% on the previous year.
It is estimated there are more than 50,000 Scots drugs addicts, with economic and social cost adding up to £2.6 billion per year.
Roger Howard, chief executive of the UKDPC, said its aim is to provide an insight into MSPs' views on drug policy.
He pointed out that there was wide cross-party support for the Road to Recovery, the Scottish Government's national drugs strategy published four years ago.
He said the finding that 60% of MSPs do not believe current policies are effective could be due to a recognition of the need for a wider social approach – such as tackling unemployment.
But he added: "Or it could be that deep down there is a suspicion that, with the way we are doing it at the moment through an enforcement or justice lens, we still have major problems.
"I think the reason is something that needs to be explored further – what we were trying to do was get an overall perspective about the way we make policy."
Howard said one aspect of concern was that much of the debate following the death-drug figures was still focused on whether methadone was "good or bad".
"What about all the other things that make recovery long-term: access to jobs, ensuring people have stable roofs over their heads, rebuilding family relationships," he said.
"Methadone and the quality of how it's prescribed is important, but one small part of something much bigger."
We asked a range of experts their views about the effectiveness of Scotland's drug policies.
Neil McKeganey, director of the Centre for Drug Misuse Research in Glasgow, argued that most politicians are not concerned enough about tackling Scotland's "longstanding" drugs problem.
He said: "We have focused on alcohol and tobacco to a level which is appropriate, given the harm of those two drugs.
"There has not been anywhere near the same level of commitment in tackling the issue of illegal drug use, which I think is shocking given the huge impact illegal drugs has in Scotland.
"I think ministers and civil servants have been persuaded over a number of years that the most they can achieve is to reduce some of the harm associated with the drug problem, rather than try to reduce the drug problem itself."
McKeganey said moves were being made in England towards "payment by results", based on the levels of recovery among clients.
He added: "I think Scotland should look very seriously at adopting a similar approach.
"At the moment we tend to fund drug treatment services on the basis they are treating – we do not know whether they are effective in getting people off drugs."
Rowdy Yates, senior research fellow and facilitator of the Scottish Addiction Studies group in the Department of Applied Social Science at Stirling University, said the debate should address the issue of whether policies should focus on helping drug users to recover or protecting society.
He said: "Both are equally valid, but arguably in the past 10-15 years we have put a lot more emphasis on protecting communities: what we do to stop people passing on infections they gain through their drug misuse and reduce crime."
He added: "Any time a politician mentions anything about reform of drug laws, they are instantly given the white feather as a conscientious objector to the war on drugs.
"That becomes an embarrassment. That is not serious political debate."
David Liddell, director of the Scottish Drugs Forum, said that Scotland's drugs problem had to be seen in the wider context of poverty, deprivation and inequality.
He said: "Looking at a whole range of health issues where Scotland comes out as the worst in Europe, it is not really surprising in a way that drug problems are similarly high.
"If you look at countries like Sweden and Holland, both have very different drug policies – one is very hardline and one in many respects very liberal.
"Yet they both have very much smaller drug problems per head of population than we do.
"Poverty and social inequality is a huge driver for the scale of Scotland's drug problem."
But he warned there was often a reluctance to debate "politically sensitive" approaches to drugs issues.
"For example, the evidence base for heroin prescribing is pretty overwhelming in terms of its potential to make a significant impact on the most chaotic group (of drug users)," he said.
"But that raises concerns about sending out the wrong messages, about being soft on drugs.
"I think that is what we need to get beyond – for people with drug problems this is not a lifestyle choice."
The need for evidence-based policies was also highlighted by Katy MacLeod, training and outreach co-ordinator at Edinburgh drugs advice charity Crew 2000, who warned of the risk of policy based on "fear, tradition and morality".
Andrew Horne, director of operations for Addiction in Scotland, said the Scottish Government's focus on recovery was a "massive advancement".
He said: "One of the things that happens when people get stuck is they don't see an exit, so there are no examples of recovery. There are now living examples that there is a way out and there are people who have done it.
"In the past, although lots of people do get out of drugs, they weren't visible and I think that will be the major shift."
Responding to the poll findings, the Scottish Government said the number of MSPs surveyed was less than half the membership of Holyrood and therefore in "no way reflects the majority view".
A spokesman added: "The Scottish Government's Road to Recovery strategy was unanimously endorsed and reaffirmed by the Scottish Parliament.
"This government has done more than any previous one to ensure that drugs policy-making is informed by a robust evidence base – our data collections are internationally recognised and we are committed to ensuring informed and well-evidenced debate and challenge."
But Labour justice spokesman Lewis Macdonald said the government's strategy had not been updated since 2008, despite evidence it that "simply isn't working".
He said: "It is deeply concerning that the Scottish Government can't tell us how many addicts are being successfully treated, nor how long addicts are being kept on methadone at huge cost to us as taxpayers."
Tory deputy leader and health spokesman Jackson Carlaw called for a move away from "parking addicts on substitute drugs to proper rehabilitation".
He added: "While methadone will continue to have a role, the Scottish Government's continued refusal to tackle addiction head on through effective treatment plans will continue to cause unnecessary deaths and suffering to families and communities affected."
Deputy Chief Constable Gordon Meldrum, director general of the Scottish Crime and Drug Enforcement Agency, said discussion on drug policy involves more than rehabilitation.
This includes tackling the supply of drugs and reducing demand.
However, while huge efforts are being made to reduce the supply of illegal drugs in Scotland, it is difficult to measure the impact of this.
"It can't be done based solely on drug seizures as the baseline changes year on year," he said. "It is difficult to address the volume of drugs making it into Scotland, therefore we don't know what proportion of drugs we are seizing.
"We need to continue trying to better define the threat."
A new survey on tackling drug abuse in Scotland has revealed that present policies are not working
Dr Des Spence, who is a GP in Glasgow, said that when methadone treatment was introduced in the 1980s, it was effective in reducing harm and had a particularly beneficial impact.
"It was incredibly chaotic back then and we saw lots of problems from injection and overdoses," he said.
"We used to have people overdosing in the toilets in the health centre and there were lots of problems with infectious diseases such as hepatitis B and C.
"Needle exchanges made a difference as well, but certainly my experience is that methadone can very much stabilise very chaotic drug-users' lives."
But he added: "I think there is an element: we have not been very successful at moving people along and I think there probably is a strong argument that we should explore more use of abstinence programmes as a way of doing that."
Dundee-based consultant psychiatrist and clinical senior lecturer in addiction psychiatry, Dr Brian Kidd, is chair of the Scottish Drugs Strategy Delivery Commission, an independent body set up by the Government to monitor the implementation of its drugs strategy. He said there had been progress, including an improvement in waiting times to access treatments and the development of a system to monitor how many people using drug services are successfully recovering, which is due to be introduced shortly.
Dr Kidd added: "There are very tangible, clear, measurable improvements in service delivery, so I am surprised people don't spot that and recognise it is there.
"I do think that the history across the UK to do with this field has always been the same. It has always been relatively easy meat, if you like.
"It has been a field where you are not going to get quick wins and therefore, if one wants to be critical, one can be."