A new study has highlighted that taking certain antidepressants for depression can actually put patients at a greater risk of developing other mental health conditions.

Serotonin reuptake inhibitors (SSRIs) and venlafazine, both commonly prescribed for depression, were linked to an increased likelihood of patients being diagnosed with mania and bipolar disorder later in their lives.

Researchers assessed the health records of over 21,000 adults from a medical centre in London, and though they had been anonymised the information showed people who had received treatment for major depression during the years from 2006 to 2013.

Their findings indicated that anyone who had taken antidepressants at some point was then at a higher risk of later being diagnosed with bipolar disorder or mania.

35.5 per cent of the sample group were prescribed SSRIs, 9.4 per cent were given mirtazapine, 5.6 per cent had taken venlafaxine and 4.7 per cent took tricyclics.

SSRIs and venlafazine were shown to have the highest risk of depression developing into other serious mental health conditions in later life, with a 34 to 35 per cent increased risk.

The results stood the same even after other influencing factors had been accounted for.

However, due to the limits of the study being based on results from one particular centre, researchers highlighted the fact that they will not be able to draw concrete conclusions about the reasons behind their findings.

They said that more research needs to be done to ascertain whether or not the issue is simply linked to latent bipolar disorder or if the medicines themselves are responsible.

More information about the study is available in academic publication BMJ.