The NHS bill for prescription drugs has risen by almost 7 per cent in a year, official figures reveal.

Statistics show the total, or net, cost to the Scottish Government hit £1.3 billion in 2015/16.

This represents an increase of 6.9 per cent compared to the final sum recorded in 2014/15.

Over the last decade, the bill for medication and other items dispensed in the community has gone up by 28 per cent, the data reveals.

The last year has also seen an increase in the total number of products dispensed.

Some 102.2 million items were issued in 2015/16, up by just more than 1 per cent on 2014/15.

Prescribing volumes have been increasing year on year, with an overall rise of 28.1 per cent from 79.8 million items in 2006/07 to 102.2 million in 2015/16.

The report stated: "This growth reflects not only the availability of new or more effective medicines, but also prescription processing and demographic changes, and the implementation of new clinical guidelines and recommendations."

The figures are contained in an annual report published by ISD Scotland.

It centres around medication and other items issued under prescription in local communities, mainly by pharmacies and dispensing doctors.

The report does not cover prescriptions dispensed in hospitals, which fall under a separate budget.

The net cost to the Government is the bill for reimbursing and remunerating pharmacies, and other dispensers, minus any charges paid by patients.

Meanwhile, drug use in Scotland has continued to decline, new figures suggest.

Statistics from the Scottish Government show 6 per cent of adults reported having used one or more illicit drugs in the last year.

The figure, published in the 2014/15 Scottish Crime and Justice Survey, was down from 6.2 per cent in the 2013/14 survey and from 7.6 per cent in the 2008/09 publication.

The survey - which is based on more than 11,000 interviews - also recorded a drop in daily drug use since the 2012/13 report.

Those reporting they used their most frequently-used drug in the last month "every day or almost every day" has fallen from 30.2 per cent in 2012/13 to 18.8 per cent in 2014/15.

Of those who reported using drugs in the last month, less than a fifth (16.6 per cent) said they had felt dependent upon the drug they used most often.

For those who had tried to cut down on the drug they used most often in the last month, almost nine in 10 said that they did not use any support services.

The majority of those who had used drugs in the last month said that it was very easy or fairly easy to get hold of their most frequently used drug.

As with the 2012/13 survey, cannabis was the most commonly-used drug.

The 2014/15 survey also includes statistics on the use of so-called legal highs, or new psychoactive substances (NPS), for the first time.

An estimated 1.6 per cent of adults reported they had taken powders, pills, herbal mixtures or crystals that are sold as 'legal highs', even if it was a long time ago.

Use of NPS was higher among younger age groups, with 4.1 per cent of 16-24 year-olds reporting having ever used legal highs, compared with 2.7 per cent of 25-44 year-olds and 0.5 per cent of 45-60 year-olds.

A blanket ban on the substances and new enforcement powers came into force across the UK earlier this year.