Scant evidence for over-the-counter depression remedies - study

Over-the-counter supplements that claim to boost mood or ease depression are backed by scant scientific evidence, according to health experts in Liverpool and Brisbane.

Herbal and nutritional supplements such as omega-3s (found in fish oil), St John’s wort, folic acid and vitamin D are frequently more popular than prescription medicines.

But according to a new review of evidence from 209 studies worldwide, they found the evidence was variable with some products only backed by a single study.

Despite their widespread availability, the study which involved Dr Rachael Frost of LJMU’s School of Public and Allied Health, found little research on the therapies, compared with psychological therapies and prescription antidepressants.

Only a few products had a significant body of evidence that they were effective at treating symptoms. These included St John’s wort, saffron, probiotics and vitamin D.

The researchers noted there was promising evidence for some herbal and nutritional supplements, where multiple studies did exist. These included folic acid, zinc, Rhodiola, lavender and lemon balm. But there is not enough evidence yet to recommend them, so more studies would be needed.

The dose and quality of over-the-counter products can also vary significantly, which can make it difficult to identify appropriate products or assess which ones work.

Uk official advice for health-care practitioners acknowledges notes there is evidence St John’s wort can help with less severe forms of depression but it also cautions in recommending it, given how much the dose, preparation and quality can vary between different herbal products.

The study also concluded these products present few safety issues, whether used alone or in combination with other treatments.

However, herbal medicines and dietary supplements also contain chemicals that can work like drugs and interact with other medications. For example, the way St John’s wort works on the body’s chemical messengers is similar to many prescription antidepressants.

So taking it alongside antidepressants can lead to a syndrome which can lead to fever and seizures in extreme instances. In rare cases, you may experience similar side effects to taking antidepressants.

However, many of these treatments are not only safe but more effective when used together with conventional treatments for depression.

Dr Frost, a senior lecturer, said, in summary: “Some herbal and nutritional supplements do appear to have a potentially beneficial effect for less severe forms of depression. But for many of these therapies there is still not enough evidence to offer definitive recommendations.”