Concerns have been voiced about the usage of anti-depressants
Doctors may be under-prescribing anti-depressant drugs despite claims the medication is being overused, a study has claimed.
Researchers from the University of Aberdeen said attempts to hit government reduction targets could be affecting prescription levels.
They analysed more than 30 GPs at four north east of Scotland surgeries.
Prof Ian Reid said: "It is more likely GPs are initiating anti-depressant treatments conservatively."
The study - published in the British Journal of General Practice (BJGP) - comes amid a general worldwide rise in anti-depressant use.
It aimed to find out how well GPs recognised and treated depression, amid claims that doctors have been prescribing anti-depressants too readily.
The researchers asked patients - who were attending the surgery for any reason - to complete depression assessment questionnaires.
The GPs - unaware of the questionnaire results - then made an assessment of the patients, and recorded whether or not they diagnosed depression.
The researchers then noted what treatments, if any, the GPs arranged, and compared those views and actions with the questionnaire results to assess if they might be giving out anti-depressants unnecessarily.
The research team said the new study cleared doctors of overprescribing.
Prof Reid said: "Our study shows that GPs are not prescribing anti-depressants unnecessarily, as has been widely assumed.
"GPs did not arrange treatment for about half of the patients who filled in our questionnaires and who had significant symptoms of depression, because they did not detect the illness at that visit."
He said: "Where anti-depressants were prescribed for patients who did not have symptoms, they were being given for reasons other than depression.
"These could be for the treatment of pain, or for patients who had been started on anti-depressants for an episode of depression prior to the start of the survey, and who were now sufficiently improved to no longer have symptoms.
"Out of the 897 patients surveyed in the study, only three were receiving anti-depressants without a clear reason for taking them."
He added: "I think the Scottish Government's policy is intended as a spur to increase the availability of non-drug treatments for depression, such as talking therapies. I'd heartily endorse that aim.
"However, in my view, it would have been better to set a target focussing on non-drug therapies, rather than on prescription volumes."
The SNP's manifesto two years ago said it aimed to reduce the use of anti-depressants by 10% by 2009 as part of a plan to improve mental health.
Public Health Minister Shona Robison said: "Our target to level off anti-depressant prescribing is not a criticism of existing practice or of anti-depressants, but reflects the need to ensure that GPs are able to call on and offer the best treatment and not just those that are the most convenient.
"It recognises that anti-depressants are just one way of helping people with mental health issues and reflects our aim of increasing the availability of other treatments such as psychological therapies, guided self-help and physical exercise.
"As this research acknowledges, our target is also designed to encourage regular review of medication to ensure it is still the most appropriate treatment."
She added: "We continue to take forward work on access times for psychological therapies."
A Department of Health spokesperson said: "Whilst some people with severe depression will benefit from a course of antidepressants, people with milder cases of depression may be better helped by psychological therapies.
"Clinicians, in discussion with patients, will decide what is the most appropriate treatment for each individual."