Over 600 people died as a result of drug use in 2012, the vast majority of whom were men, new figures have shown.

According to the latest figures from the National Drug-Related Deaths Index, which is published by the Health Research Board (HRB), 633 died in 2012, a slight drop on 2011's figure of 645.

Of these, 350 people died from poisoning, i.e. as a result of the toxic effect of drugs on the body, while 283 deaths were among drug users and included trauma deaths such as hanging and deaths from medical causes, such as heart problems and liver disease.

Among the poisoning deaths, three out of four were men and half were under the age of 40. Alcohol was involved in one-third of these deaths, as were benzodiazepines (sedatives). Methadone was involved in one-quarter of the deaths and in most of these cases, it was mixed with another drug.

In fact, at least half of the poisoning deaths involved a mixture of drugs - known as polydrug use. Since 2004, there has been a 60% increase in the number of polydrug-related deaths.

Meanwhile, at least one-third of people who died from poisoning had a history of mental illness.

Among the 283 non-poisoning deaths, 138 were due to trauma, mostly hanging (80%). Half of these deaths related to people under the age of 30 and 80% were men.

At least half of people who died from traumatic causes had a history of mental illness.

When it came to deaths related to medical causes, such as liver disease, most of those who died were aged between 35 and 59 and men made up almost three in four of these cases.

According to HRB chief executive, Graham Love, the purpose of these figures is to provide ‘solid evidence to inform efforts in tackling problem drug use and ultimately save lives'.

"Our data outlines the key contributors to the deaths. What is clear is that alcohol remains the substance implicated in most poisonings, polydrug use features in more than half of poisonings and we continue to see an increase in the number of people dying by hanging," he commented.

While welcoming the small fall in drug-related deaths, Health Minister, Leo Varadkar, admitted that such deaths ‘still remain at an unacceptable level'.