People with certain metabolic risk factors—obesity, high blood pressure, and high cholesterol, for example—are more likely to develop type 2 diabetes if they’re also depressed.
Previous research has suggested a link between diabetes and depression, but the new study suggests it’s the combination of depression and other risk factors that contribute to increased risk.
The study divided 2,525 adults between the ages of 40 and 69 in Quebec, Canada, into four groups: those with both depression and three or more metabolic risk factors; two groups, each with one of these conditions but not the other; and a reference group with neither condition.
In a departure from previous findings, the researchers discovered that participants with depression, alone, were not at significantly greater risk of developing diabetes than those in the reference group.
The group with metabolic symptoms but not depression was around four times more likely to develop diabetes.
Those with both depression and metabolic risk factors, on the other hand, were more than six times more likely to develop diabetes, with the analysis showing the combined effect of depression and metabolic symptoms was greater than the sum of the individual effects.
A vicious cycle
The researchers believe depression, metabolic symptoms, and the risk of developing diabetes interact in a number of ways. In some cases, a vicious cycle may emerge with depression and metabolic risk factors aggravating one another.
Evidence shows people suffering from depression are less likely to adhere to medical advice aimed at tackling metabolic symptoms, whether it be taking medication, quitting smoking, getting more exercise, or eating a healthier diet. Without effective management, metabolic symptoms often worsen and this can in turn exacerbate the symptoms of depression.
Beyond these behavioral aspects, some forms of depression are associated with changes in the body’s metabolic systems, which can lead to weight gain, high blood pressure, and problems with glucose metabolism. Meanwhile, some antidepressant medications can also cause weight gain.
The researchers emphasize that not all cases of depression are the same—only some people with depression also suffer from metabolic problems. When it comes to improving health outcomes, identifying those patients who suffer from both depression and metabolic symptoms as a subgroup and adopting an integrated treatment approach may be crucial to breaking the cycle.
“Focusing on depression alone might not change lifestyle/metabolic factors, so people are still at an increased risk of developing poor health outcomes, which in turn increases the risk of developing recurrent depression,” says Norbert Schmitz, an associate professor in psychiatry at McGill University and lead author of the study published in the journal Molecular Psychiatry.
The Canadian Institutes of Health Research and the Fonds de recherche du Québec – Santé, Canada, funded the study.
Source: McGill University