Working through an exercise in gratitude or counting your blessings can often have positive health benefits and lift our mood – but it isn't actually much help when it comes to properly dealing with symptoms of depression and anxiety, new research has found.

Weighing up the evidence from 27 previous studies, covering 3,675 individuals in total, researchers observed only a "small effect" on depression and anxiety, suggesting better options are available when it comes to treating these conditions.

And while a grateful attitude can often have knock-on effects that are very welcome, the team behind the new meta-study is asking for caution in treating gratitude 'interventions' as a viable form of treatment.

"For years now, we have heard in the media and elsewhere about how finding ways to increase gratitude can help make us happier and healthier in so many ways," says psychologist David Cregg, from Ohio State University.

"But when it comes to one supposed benefit of these interventions – helping with symptoms of anxiety and depression – they really seem to have limited value."

Two of the most common exercises in focusing on gratitude are keeping a journal of three things that went well every day, and writing a letter expressing gratitude to someone who's made a difference in your life.

But when compared with exercises unrelated to gratitude – like writing about a class schedule – these steps don't seem to have much of an impact in terms of relieving anxiety or depression.

In other words, telling people who show symptoms of being anxious or depressed to be more grateful for the good things in their lives may not be all that effective.

"There was a difference, but it was a small difference," says psychologist Jennifer Cheavens, from Ohio State University. "It would not be something you would recommend as a treatment."

The researchers point to other options like cognitive behavioural therapy as being better for tackling anxiety and depression in the long run.

That's not to say trying to concentrate on the positives is a waste of time. Exercises in gratitude have been shown to have benefits in terms of improving relationships and in getting people to exercise more, for example.

But for treating anxiety and depression, not so much. Previous studies may have suffered to varying degrees from problems with assessment methods, risk of bias, control groups measurements and the placebo effect, the researchers note.

That said, this isn't yet the final word on the subject: this new research only involved two clinical samples, and only five studies that included an analysis of anxiety. What's more, it focused on gratitude interventions – specific exercises – rather than the effects of a more grateful attitude in general.

"Based on our results, telling people who are feeling depressed and anxious to be more grateful likely won't result in the kind of reductions in depression and anxiety we would want to see," says Cheavens.

"It might be that these sort of interventions, on their own, aren't powerful enough or that people have difficulty enacting them fully when they are feeling depressed and anxious."

The research has been published in the Journal of Happiness Studies.