MINIMUM pricing could trigger a spike in drug overdose deaths as heavy drinkers swap alcohol for an addiction to pills, an NHS consultant has warned.

Dr Michael Colvin, a doctor in Forth Valley, said there had been little research done into the risk of “addiction transfer” as a result of increasing the minimum unit price [MUP] on alcohol in Scotland.

Sheffield University researchers have forecast that an estimated 2,036 deaths would be avoided over the first 20 years after the proposed 50 pence per unit policy comes into force, but Dr Colvin said these predictions only take into account fatalities linked to alcohol consumption and not other forms of substance abuse.

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Writing in the Herald, Dr Colvin said: "Consumers of large volumes of cheap alcohol must be vulnerable to drug use...we all want MUP to be a success, but some unhappy Scots, finding their favourite tipple out of reach, may simply reach for the painkillers".

Dr Colvin, a paediatrician at Forth Valley Royal in Larbert, said he was interested because the number of children being taken into care has more than doubled since 2000, in many cases as a result of their parents' abuse of alcohol and drugs.

He added that this was a phenomenon affecting the generation born in the 1960s and 70s, whose life expectancy was now falling behind those born in the 1940s and 50s. It is a trend already observed in the United States where so-called "deaths of despair" among middle aged people - mainly white Americans without college degrees - from suicide, alcohol abuse and drugs, especially opioids, has led to an overall fall in average US life expectancy for the first time in nearly a century.

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Dr Colvin said: "I don't think minimum pricing is a bad idea, it's just that I think there are other things going on in the population that might make it appear like a failure.

"If it's not dealing with the underlying problem [of despair], there's a potential for the problem just to change into an opioid problem or something else."

The Scottish Government is aiming to introduce minimum pricing from May this year.

Dr Eric Carlin, director of Scottish Health Action on Alcohol Problems (SHAAP), said he was "not convinced" addiction transfer would occur.

He said: "There wasn't any evidence from Canada that [minimum pricing] caused this big shift into drug misuse.

"The Scottish evaluation of the policy won't just be looking at alcohol-related deaths, it will be looking at consequences of the policy - including unintended consequences. Nobody in public health would be arguing for a policy that made more people ill and more people die. So if there is a drift into other unhealthy behaviours, that would be something to be concerned about."

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However, Dr Colvin said opiate deaths in Canada had gone "through the roof", and that it was possible Canadian public health experts simply had not "put two and two together".

A Scottish Government spokesman said: “There is a clear and proven link between alcohol consumption and harm. That is why our focus is on implementing minimum unit pricing on May 1 2018, so we can start to tackle the cheap, high strength alcohol that causes so much damage to families and communities across the country."

He added that mental health spending and staffing were both set to increase.

He said: “We are in the process of reviewing of our national alcohol and drug strategies, which will reinvigorate our approach and help us respond to the new challenges and problems each individual is facing.

“We are also implementing a new Mental Health Strategy. Our direct support of Mental Health Innovation and Improvement is increasing by £17 million to £70.2m next year – including our commitment to increase the mental health workforce by an extra 800 workers over the next five years.”