Antidepressants should be given to patients at lower doses, researchers have said.

A new study, led by the University of Oxford, suggests prescribing at the bottom end of the recommended amount achieves “optimal balance” between effectiveness and limiting adverse side effects.

Professor Andrea Cipriani, co-author of the study, said current UK guidelines on prescribing the drugs for depression are “conflicting” and suggested they should be updated.

“When I see patients in my clinic and we agree on prescribing an antidepressant for their depressive episode, the big challenge is not only to prescribe the right medication but also to find the best dosage for each individual, optimising efficacy and reducing side effects,” she said.

“Current practice guidelines provide conflicting recommendations.”

The analysis, published in journal The Lancet Psychiatry, included data on 19,364 participants.

The research focused on the most frequently prescribed antidepressants in the UK, including five selective serotonin reuptake inhibitors (SSRIs), venlafaxine and mirtazapine.

The lower range of licensed doses was found to achieve “optimal balance between efficacy, tolerability, and acceptability in the acute treatment of major depression”.

Commenting on the findings, Professor Sir Munir Pirmohamed, from the University of Liverpool, said: “Medicines are developed on a one-dose-fits-all strategy, and typically the dosing instructions state that the dose should be titrated to the maximum tolerated doses, which inevitably ends up as the maximum licensed dose.”

He added: “We need to start developing methodology for personalising dosing for patients, not only for drugs used for psychiatry, but also in many other conditions.”