DEPRESSION - Part 4

Sleep quality among the weight-trainers had improved by 35 per cent but become worse among the control group.

"Each group received the same amount of attention but the improvement in depession measures was two to three times better among the weight trainers," Singh said.

"Two years later a third of the weight-trainers were still lifting weights and they still had significantly lower rates of depression."

Many studies have confirmed the benefits of exercise in treating depression. It is widely recognised as being one of the safest and most effective therapies for the disorder. But results in these studies have been variable, ranging from modest benefits to far-reaching improvements that are comparable with the gains produced by drugs.

Singh concluded that different studies of exercise were in fact examining different treatments.

This year he published a second study in which people over 60 with major depression were divided into three groups and studied over eight weeks. One group received practitioner care, which involved patients following their GPs directions.

The second group performed low intensity exercise, lifting weights that were 20 per cent of their maximum capacity.

The third group undertook high-intensity exercise, lifting weights at 80 per cent of their maximum capacity.

The high-intensity weight-trainers did much better than the other two groups, experiencing a 60 per cent reduction in their depressive symptoms. The other two groups achieved about a 30 per cent reduction in symptoms, comparable with the improvements placebos usually achieve in depression. "We don't know exactly why high-density exercise helps people with depression," It may be a purely biological mechanism involving changes in neurotransmitters. Neurotransmitters are chemicals that aid communication between brain cells and effect mood. In depression levels of some neurotransmitters are greatly reduced. Drugs designed to treat depression aim to increase levels of neurotransmitters, in particular serotonin.

"High-intensity exercise changes hormones and increase levels of dopamine, noradrenaline and serotonin (which are all neurotransmitters," Singh says. "The (graphed) curves for response (in using exercise to treat depression) are exactly the same as the curves for drugs." But unlike drugs, exercise has positive side effects. "Tablets can cause constipation, confusion and other side-effects," he said.

"But exercise treats a whole lot of physical problems as well as the depression.

There is more and more evidence that depression is linked to poor health and a whole lot of diseases.

"Exercise improves general health and it reduces inflammation and improves circulation, which can enhance brain function as well as general health."

Singh would like to see high-intensity exercise used as the first line of treatment for patients with depression. He believes weights are the best form of exercise as they are safe, providing patients are given basic instructions on their proper use, and can be used in a gym or at home.

But Hickie says drugs will continue to be widely used, as supervised exercise regimes receive no government support and severely depressed patients may require a course of drugs before they can summon the energy and motivation to undertake exercise or other behavioural therapies.

Nowadays Ruth Watson is free of depression, thanks to years of psychological therapy and a maintenance dose of Prozac.

Life is good. She has a loving family and meaningful work. She is a human resources consultant and chairs blue Voices, the patient and carer arm of beyondblue.

"Working with beyondblue is good for me, it gives me some kind of ongoing cathartic therapy, Ruth Watson says.

"I've also been fortunate enough to have had a good doctor and a yery supportive husband, who have helped me to see things differently and recondition my thinking."

But her illness still looms large in her life. "I still need Prozac and I know there is still the risk that I could have a major depressive episode."