The number of deaths involving so-called legal highs more than doubled last year, according to new figures.

Last year there were 113 deaths where New Psychoactive Substances (NPS) were present, compared with 47 in 2012.

NPS, which are defined as new chemical substances that affect brain function, were implicated in 60 deaths compared to 32 in 2012, though other substances were also implicated in 55 of the 60 deaths.

The number of drug-related deaths in Scotland decreased by 9% last year to 526, according to new statistics from the National Records of Scotland.

There were 32 drug deaths among the under-25s, the lowest since records began in 1996, while just over two-thirds (68%) of deaths were amongst those aged-35 and over.

Three-quarters of those who died in 2013 were men.

Community Safety Minister Roseanna Cunningham said: "The number of drug deaths dropped by 9% last year and that is to be welcomed. The hope is that increases in previous years have now come to end and numbers are now levelling off.

"However behind each of these figures is a grieving family and first and foremost we must recognise we have lost 526 people to drug use. I want to offer my sincere sympathies for the lives lost.

"These statistics are a product of a long legacy of drug misuse among older users. We are clear that one death is one too many, that's why we are funding the Scottish Drugs Forum to work with older users and why almost 4,000 naloxone kits were issued through our prevention programme to people at risk of overdose in 2012/13, potentially saving more than 350 lives."

She also said that the Scottish Government is committed to doing everything it can to restrict access to NSPs and to educate people about their dangers.

The figures showed that just over nine in 10 deaths were of people who took more than one drug, and perhaps alcohol. Only 9% had only one drug, and perhaps alcohol, present in the body.

Roy Robertson, chair of the National Forum on Drug Related Deaths, said: "Today's figures are a familiar representation of a complex problem.

"The welcomed reduction in total numbers of drug related deaths is in line with fluctuations seen over a long time period but, hopefully, shows an improving situation. In addition the pattern of multiple drug ingestion leading to a fatality is continued from previous years."

Carole Kelly, chief executive of drugs information charity Crew 2000, warned of the dangers of NPS.

She said: "NPS may be cheaper than known illegal drugs and we are aware of people using them across different age ranges and social groups.

"People who haven't used drugs before are at risk if they do not have experience or credible information with which to make informed choices about NPS and people who have previously used other drugs may not be aware of additional risks and consequences of use."