An international evidence review has found that certain nutritional supplements can increase the effectiveness of antidepressants for people with clinical depression.
Omega 3 fish oils, S-adenosylmethionine (SAMe)*, methylfolate (bioactive form of folate) and Vitamin D, were all found to boost the effects of medication.
University of Melbourne and Harvard researchers examined 40 clinical trials worldwide, alongside a systematic review of the evidence for using nutrient supplements (known as nutraceuticals) to treat clinical depression in tandem with antidepressants such as SSRIs**, SNRIs^ and tricyclics^^.
Head of the ARCADIA Mental Health Research Group at the University of Melbourne, Dr Jerome Sarris, led the meta-analysis, published today in the American Journal of Psychiatry.
"The strongest finding from our review was that Omega 3 fish oil - in combination with antidepressants - had a statistically significant effect over a placebo," Dr Sarris said.
"Many studies have shown Omega 3s are very good for general brain health and improving mood, but this is the first analysis of studies that looks at using them in combination with antidepressant medication.
"The difference for patients taking both antidepressants and Omega 3, compared to a placebo, was highly significant. This is an exciting finding because here we have a safe, evidence-based approach that could be considered a mainstream treatment."
The University of Melbourne research team also found good evidence for methylfolate, Vitamin D, and SAMe as a mood enhancing therapy when taken with antidepressants. They reported mixed results for zinc, vitamin C and tryptophan (an amino acid). Folic acid didn't work particularly well, nor did inositol.
"A large proportion of people who have depression do not reach remission after one or two courses of antidepressant medication," Dr Sarris said.
"Millions of people in Australia and hundreds of millions worldwide currently take antidepressants. There's real potential here to improve the mental health of people who have an inadequate response to them."
Dr Sarris said medical professionals may be hesitant to prescribe nutraceuticals alongside pharmaceuticals, simply because there has been a lack of scientific evidence around their efficacy.
"Medical practitioners are aware of the benefits of omega 3 fatty acids, but are probably unaware that one can combine them with antidepressant medication for a potentially better outcome," he said.
The researchers found no major safety concerns in combining the two therapies, but stressed that people on antidepressants should always consult with their health professional before taking nutraceuticals and should be aware these supplements can differ in quality.
"We're not telling people to rush out and buy buckets of supplements. Always speak to your medical professional before changing or initiating a treatment," Dr Sarris said.
The researchers are currently conducting a National Health and Medical Research Council study using a combination of these nutraceuticals for depression.
Notes about definitions:
* SAMe is a molecule that formed naturally in the body. It can also be made in the laboratory. SAMe is involved in the formation, activation, or breakdown of other chemicals in the body, including hormones, proteins, phospholipids, and certain drugs. SAMe is involved in a range of brain chemical processes that are critical to the maintenance of good mood
** SSRIs: Selective Serotonin Reuptake Inhibitors are a common type of antidepressant that inhibits the brain's re-absorption of the 'feel-good' chemical serotonin. Common types include citalopram, fluoxetine and sertraline.
^ SRNIs: serotonin and noradrenaline reuptake inhibitors (SNRIs) are a group of antidepressants, and include: desvenlafaxine, duloxetine and venlafaxine, among others. These drugs increase the amount of mood regulating neurotransmitters - noradrenaline and serotonin - in the brain.
^^ tricyclics are first-generation antidepressants, such as doxepin, are designed to increase levels of norepinephrine and serotonin, two neurotransmitters, and block the action of acetylcholine, another neurotransmitter.