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New figures reveal that the NHS in England spent more than £270m on antidepressants last year - a massive 23% increase on 2010. The health service spent almost £1m a week more on the drugs than the year before.

Antidepressant use has been growing rapidly for decades. In 1991, English pharmacies handed over nine million items. In 2001, it was 24.3 million. Now the number has grown to 46.7 million prescriptions issued - a 9.1% rise on the previous year.

So what do we make of this? Are we witnessing a significant decline in mental health, exacerbated, perhaps, by the financial crisis? Is the country becoming addicted to popping pills? Or is this evidence of changes in prescribing practice, more people being diagnosed and given pills for longer?

Happiest places in the UK Well-being statistics released last week showed islands in north of Scotland to be least anxious

Leicestershire, inner London, Middlesbrough, South Ayrshire and Peterborough most anxious

Bath and North Somerset ranked highest for life satisfaction, Merthyr Tydfil ranked lowest

And Blackpool ranked lowest when asked how happy they felt yesterday What are the top five happiest parts of the UK?

It can't be, as some GPs have suggested, that the rise in the number of "items" is down to surgeries prescribing smaller doses more often - the amount spent on ingredients is also rising fast. All the evidence points to a rapid increase in the number of pills being swallowed.

The rise comes at a time when doctors working for the NHS in England are being encouraged to move away from antidepressants for the treatment of mild depression and anxiety in favour of psychological therapies.

I first wrote about this issue in 2009 when I obtained figures under freedom of information. I suggested then that the prescribing statistics painted a troubling picture of well-being in northern England.

These latest figures show the same clear geographical variation in prescribing rates for antidepressants - with an interesting correlation to the well-being data published last week.

Blackpool is the place with the highest use of antidepressants in England - an astonishing 1,430 prescriptions signed for every thousand patients in the primary care trust. The PCT issued 221,000 items with 155,000 people on its books.

The lowest rates of antidepressant use are predominantly in London - which may represent markedly different prescribing practice in the capital

Blackpool also emerged as England's unhappiest place in last week's well-being survey data, with 36% of adult residents giving a score of 6/10 or less when asked to rate how happy they were the day before.

According to the latest figures, the next five places with high prescribing rates for antidepressants are all clustered in the North-East of England - Redcar and Cleveland, County Durham, Gateshead, Newcastle and Sunderland. County Durham, incidentally, was the second most unhappy place in England according to the well-being figures.

The places with the lowest rates of antidepressant use are predominantly in London - a finding which may represent markedly different prescribing practice in the capital but is also, perhaps, explained by the mobility of urban populations. The data is based on GP lists which are known to be more out of date in city areas where patients move in and out more often.

Top 10 and bottom 10, plus bottom 10 outside London

The official guidance to GPs from the National Institute for Clinical Excellence (Nice) says this: "Do not use antidepressants routinely to treat persistent sub-threshold depressive symptoms or mild depression because the risk-benefit ratio is poor."

Media playback is unsupported on your device Media caption Dr Clare Gerada: Anti-depressants save lives

Instead, GPs are encouraged to offer cognitive behavioural therapy (CBT) and structured group physical activity programmes. The latest figures suggest this guidance may not be followed through by general practitioners, despite a huge increase in the availability of CBT in England.

A programme called Improving Access to Psychological Therapies (IAPT) was begun in 2007, since when the NHS has trained and employed almost 4,000 psychological therapists with a further 2,400 to be trained in the next couple of years.

A paper in the British Medical Journal in 2009 attempted to explain the rise in antidepressant prescribing and concluded that it was down to "small changes in the proportion of patients receiving long term treatment". In other words, once people are given their first pills they tend to stay on them for years, if not decades.

Antidepressants can be very effective for people with depression and anxiety, and it may be that better diagnosis is revealing large numbers of new people who are benefiting from some excellent drugs now available.

But there must be a concern that what we are actually seeing is a health service too ready to give patients pills for mental conditions which are helped better in other ways.