‘Lifestyle therapy’ may be as effective as seeing a psychologist for depression

In 2012, when Professor Adrienne O’Neil started working on the SMILEs trial, the idea was to find out if a Mediterranean-style diet might be a therapeutic strategy for major depression. Food, they found, could indeed improve mood.

“Since then, findings have been replicated four times,” says O’Neil, of Deakin’s Food & Mood Centre. But when she and her colleagues went out to share the knowledge with health professions including GPs, there was a common concern.

They’d ask how, by referring a person to a dietitian or an exercise physiologist, they could ensure they weren’t depriving their patient of care by not sending them to a psychologist.

“At that time, we couldn’t answer that question,” she reflects today.

O’Neil and her team decided they needed to do a head-to-head comparison between a dietary intervention coupled with exercise to make it a form of lifestyle therapy versus the gold-standard of psychotherapy using cognitive behavioural therapy (CBT).

For a new world-first study, published in Lancet Regional Health, 182 participants, with symptoms of moderate depression, were randomly assigned to an eight-week program involving group video conferencing sessions of lifestyle therapy or CBT.

The lifestyle therapy, overseen by an accredited practising dietitian and an accredited exercise physiologist, focused on a high-fibre, plant-based diet, with good fats, nuts and seeds. Junk food intake was to be limited to special occasions, while physical activity goals centred around enjoyable movement. There were no intense workouts required.

The psychology sessions taught CBT and mindfulness, administered by registered psychologists.

At the end of the eight weeks, participants receiving lifestyle therapy experienced a 42 per cent improvement in their depressive symptoms compared to a 37 per cent improvement among CBT participants.

O’Neil hypothesises that there were psycho-social benefits: “When you start to achieve goals there is a feeling of accomplishment,” she says.

But there are also plausible biological explanations for the improvements among the lifestyle group, including that our body functions better when we fuel it well; there is less inflammation, which is linked to depression; and our microbiome improves. With good nutrition, our gut bacteria produce compounds and chemicals, including serotonin, GABA dopamine and cortisol, that are key for brain health, and mental wellbeing.

They also found that lifestyle therapy was as cost-effective as psychological treatment.

With increasing numbers of people experiencing a mental health disorder, there is unprecedented demand for support and people are waiting longer to see a psychologist.

The findings from the new study could be applied in various ways, O’Neil suggests. Those with low-grade depression might opt for lifestyle therapy first (using appropriately upskilled dietitians and exercise physiologists); people could use it while they wait to see their psychologist; or for those with more severe forms of mental illness, it could be used adjunctively.

“It opens up a lot of avenues for multidisciplinary care in mental health care,” O’Neil says, adding that their next study involves looking at the effects on a larger cohort with more severe depression or bipolar.

Dietitians Australia President Tara Diversi said: “This study shows how critical it is for dietitians to be funded through Medicare for mental health care.”

Clinical psychologist and Beyond Blue spokesperson, Dr Luke Martin, said the results of the study are promising.

“They reinforce some of what we already knew: that those lifestyle factors of good nutrition and physical activity can have a strong effect in our mental health and can reduce symptoms of depression,” Martin says.

“I think they extend our knowledge by showing that these interventions can be delivered by non-mental health professionals, and achieve similar results to traditional therapy.”

He adds that psychologists remain critical, have scope far greater than CBT, and that people should not attempt to treat their depression on their own by just exercising more, for instance. But, he adds that with training, so that practitioners can detect when a person needs to be referred to a higher level of support, it can help to diversify the mental health workforce and meet the demand.

“It’s really about having a treatment plan in place that has the right mix of options and supports for you.”

The Food and Mood Centre is currently recruiting Australians with major depression or bipolar for the HARMONE trial. Find out more information here or email: harmone@deakin.edu.au

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