From the points of view different researchers, the potential for a drug to be addictive can be judged in terms of the harm it causes, the street value of the drug, the extent to which the drug activates the brain's dopamine system, how pleasurable people report the drug to be, the degree to which the drug causes withdrawal symptoms, and how easily a person trying the drug will become hooked.

There are other facets to measuring the addictive potential of a drug, too, and there are even researchers who argue that no drug is always addictive.

Given the varied view of researchers, then, one way of ranking addictive drugs is to ask expert panels. In 2007, David Nutt and his colleagues asked addiction experts to do exactly that - with some interesting findings.

1. HEROIN

Nutt et al's experts ranked heroin as the most addictive drug, giving it a score of 2.5 out of a maximum score of 3. Heroin is an opiate that causes the level of dopamine in the brain's reward system to increase by up to 200 per cent in experimental animals.

In addition to being arguably the most addictive drug, heroin is dangerous, too, because the dose that can cause death is only five times greater than the dose required for a high.

Heroin also has been rated as the second most harmful drug in terms of damage to both users and to society. The market for illegal opiates, including heroin, was estimated to be $68 billion worldwide in 2009.

2. ALCOHOL

Although legal in the US and UK, alcohol was rated as the second most addictive substance by Nutt et al.'s experts (scoring 2.2 out of a maximum of 3).

Alcohol has many effects on the brain, but in laboratory experiments on animals it increased dopamine levels in the brain's reward system by 40-360 per cent - and the more the animals drank the more dopamine levels increased. Continue reading

Source & Image

• Stuff, from an article by Andrew Bowman, Lecturer in Psychology and Neuroscience, University of St Andrews.

William P. Blatty is promoting his book titled "Finding Peter; The True Story of the Hand of Providence and Evidence of Life After Death".

Aleteia reported Mr Blatty told a Washington, DC audience that he believed his son was in a righteous state when he died in 2006, having recently been to Confession, at his mother's urging.

"I'm good with God," his son told him.

Peter, a former heroin user, died of heart failure after eating pizza and drinking beer one night.

Two months later, Mr Blatty noticed something unusual about a favourite tree of Peter's in the family backyard in Maryland.

It had grown buds in the middle of winter, but lost them the next day.

Later, a broken halogen light stayed on for half a minute.

Mr Blatty does not discount the possibility that each incident was an unexplained natural event; the subtitle of his book uses the word "evidence" rather than "proof" to show that life extends beyond the grave.

In his latest book, Mr Blatty wrote that during the seven years since his son's death, "he has given Julie, his mother, and me unremitting strong evidence that his death, like all human death, is a lie".

Mr Blatty said his latest book is the culmination of a writing career which he views as an apostolic act.

If there are demons, there must be God, he concluded.

Mr Blatty wrote his best-selling novel "The Exorcist", later made into a famous movie, after hearing about successful and previous failed attempts by priests to exorcise a Maryland boy.

In 2013, Mr Blatty petitioned the Vatican to revoke the Catholic status of his alma mater Georgetown University, unless the institution implemented Ex Corde Ecclesia, the apostolic constitution that defines the mission of Catholic colleges.

Sources

• Aleteia
• Image: Huffington Post