The risk of coronary heart disease and a cluster of conditions known as metabolic syndrome increases soon after otherwise healthy, but depressed people are started on psychiatric drugs, putting them at risk for an early death, Canadian researchers are reporting.
Antidepressants, antipsychotics and other psychoactive drugs are the second most-prescribed drug class in the country, second only to cardiovasculars, according to prescription drug-tracking firm IMS Health Canada.
Across Canada, retail pharmacies last year dispensed 61.2 million prescriptions for psychotherapeutics, worth nearly $2.4 billion.
"Usually five of the top 10 prescribed medications worldwide are psychiatric drugs. We need to start looking at the impact of these medications on other systems," says Dr. Valerie Taylor, a professor in psychiatry and behavioural neurosciences at St. Joseph's Healthcare and McMaster University in Hamilton.
In a study published this week in the Canadian Journal of Psychiatry, Taylor and her colleagues followed 52 patients, age 16 to 40, newly diagnosed with bipolar disorder or major depressive disorder.
Many were university students who had become ill for the first time. All were "treatment naive" -- they had never before been treated for a psychiatric illness.
At the start of the study, researchers measured waist circumference, blood pressure, blood fats and other markers of metabolic syndrome -- the name for a grab-bag of health problems that increase the risk of diabetes and cardiovascular disease.
People with metabolic syndrome are twice as likely to die from, and three times as likely to have a heart attack or stroke compared to people without the disorder. They also have up to a nine-fold greater risk of developing Type 2 diabetes.
At the start of the study, 11 per cent of patients met diagnostic criteria for metabolic syndrome, similar to the general population. This increased to about 17 per cent after two-years of followup.
"It was actually quite disturbing, given that this was a young, healthy population when we started," Taylor said. "If this had been in a regular clinic, the patients would never have been monitored, simply because no one thinks that a healthy 29-year-old needs to have their glucose checked regularly because they have a mental illness."
The risk of having a heart attack or stroke in the next 10 years also increased for both sexes over time, but was higher for women.
All medication classes -- antidepressants, mood stabilizers and "atypical," or newer antipsychotics -- appeared to increase the risks.
People diagnosed with depression lose 25 years or more of life expectancy, Taylor said.
"The whole focus of my research has been trying to understand why giving an 18-year-old girl a diagnosis of depression means that she is much more likely than her counterpart to have a heart attack when she's 55 -- even if everything else between the two of them is the same," Taylor says.
One in five people will experience depression at some point during their lifetime.
"We're not talking about a small group of people who are affected by this. This is something that's affecting a large segment of the population.
"The medications used to treat depression are life-saving," Taylor says. "But these medications also come with a host of side-effects," she said -- especially weight gain. Many of the patients in the study gained weight rapidly.
"People can gain as much as 10, 20 to 30 pounds over the course of a year," Taylor said. "Over the course of two years, we were definitely seeing significant changes" in weight.
The study has one of the longest followup periods published so far.
"Mental health treatments are not like antibiotics -- you don't take them for six weeks and then stop," Taylor said, "despite the fact that that's how most studies are designed.
"These are medications that are taken for years, if not lifelong, because depression and bipolar disorder are not illnesses we can cure. They're illnesses we can treat."
She said patients with depression need early screening and appropriate treatment for cardiovascular disease and metabolic syndrome.