As diseases, they seem to be worlds apart, but could depression and related psychiatric conditions actually be treated in much the same way as diabetes?
Intriguing new research detailed at a Toronto conference Monday suggests that insulin does play a central role in triggering mood disorders, and that tackling metabolic imbalances in the brain could turn upside down how medicine combats the little-understood ravages of mood disorders.
"New treatments are not going to be simple modifications of Prozac, but something completely different," Dr. Roger McIntyre, a psychiatrist and University of Toronto researcher, told the conference. "We're going to have a very novel array of not just pharmacological, but behavioural treatments for our patients."
A trial completed this month at Toronto's Mount Sinai Hospital saw bi-polar patients receive insulin through a nasal inhaler. Though the findings have yet to be fully tabulated or published, the results appear to be positive, said Dr. McIntyre, who led the research.
Separate studies are looking at using other treatments typically employed for diabetic and obese patients -such as special diets and even weightloss surgery -to try to address mood problems.
A revolution in treatment of mood disorders -collectively the number one cause of disability in Canada -is desperately needed, Dr. McIntyre suggested to the Baycrest institute's neuroscience of emotion conference. Modern, SSRI anti-depressants, relatively free of harmful side effects, are widely used, but even the most cutting-edge drugs today are no more effective in treating depression than what was on the market in the 1950s, said Dr. McIntyre.
Baycrest describes itself as a premier academic health sciences centre focused on aging, affiliated with the University of Toronto. It includes the Rotman Research Institute, one of the world's top brain institutes, and aims to ''transform aging.'' The Baycrest forum also featured some research that dealt with dementia, which will be front and centre at a separate conference this week in Toronto of the organization Alzheimer's Disease International.
As many as 80% of majordepression patients are not helped by the pharmaceutical arsenal that doctors currently have at their disposal. And the evidence indicates that the serotonin and other "monoamine" neurotransmitters that those drugs all target may be linked to depressive symptoms in some patients, but having nothing to do with its cause, said Dr. McIntyre.
"The future of psychiatry will no longer involve these kinds of drugs," he said.
Dr. McIntyre said he began theorizing about a connection between metabolism and mood disorders about a decade ago when he noticed that many of his patients were also diabetics or obese, and that those individuals tended to be among the most difficult to treat.
In fact, 50% to 75% of depression and bi-polar patients are either diabetic, obese or overweight. And subsequent research has shown that insulin plays a significant role in the development of the brain and other neurological functions.
"If you step out of psychiatry and you look into another area, like diabetes, a condition defined by insulin problems, those individuals on the surface have many of the same problems that our patients have," he added. "They have lots of mood disturbances and cognitive changes . and their brains are as affected as our patients."
The theory seems to apply to more than just the diabetic or obese, however. The brain insulin problems that seem to be linked to mood disorders have also been identified in patients who suffer from major depression, but are otherwise healthy and fit," said Dr. McIntyre.
The research is still at an early stage, though, and even if the ideas now being explored end up being fruitful, it would likely be years before any resulting drugs make it onto the market.