Canadian teenagers who attend schools in areas with high income inequality are more likely to suffer from depression than those in areas with low income inequality, according to the first study of its kind in Canada.

It is already well understood that being poor can negatively affect mental health, said co-author Roman Pabayo, an epidemiologist and associate professor in the University of Alberta's School of Public Health. But, he adds, "On top of the negative aspect of living in poverty, if there's a large gap between rich and poor in the area where they're living or going to school, that can have a further adverse effect on teenage mental health."

PhD candidate Claire Benny, who led the new research, analyzed data from the Cannabis, Obesity, Mental health, Physical activity, Alcohol, Smoking and Sedentary behavior (COMPASS) study, which includes responses from 61,642 students in 43 census districts in Quebec, Ontario, Alberta and British Columbia. The students were asked a series of questions to measure their psychosocial well-being and mental health.

Her study showed that higher levels of income disparity in a school population—where some students come from poor families and others from wealthier upbringings—affect students' psychosocial well-being, including feelings of inferiority and lack of self-esteem. This, in turn, often leads to depression. In these schools, the effects can be seen in students from both low-income and higher-income families.

"We see rising income inequality and rising depression among adolescents, so we have a wicked problem here," said Benny.

Depression is among the most common mental illnesses in Canada, and teenagers have one of the highest rates, with nearly 28.5% reporting symptoms such as feeling sad or hopeless in the previous year, according to the Canadian Mental Health Association.

Benny said income inequality has been on the rise in Canada since the 1990s, especially in the largest cities such as Montreal and Toronto.

Pabayo said a second study by his team, recently published in the journal Health Education & Behavior, suggests income inequality in schools also leads to higher incidences of bullying among boys. Girls tend to cope with the effects of income disparity by internalizing their feelings, which can lead to depression and anxiety, he said. Boys tend to externalize with aggressive behavior, becoming the perpetrators or victims of bullying, or both.

Given that adolescents spend the majority of their waking hours in school, these findings should be a wake-up call for education and mental health experts, say the researchers.

No one wants to return to a time when poor children went to inadequate schools in low-income areas and wealthier students attended better schools elsewhere, said Pabayo, noting that a mix of incomes and racial backgrounds is healthy for a school population. But he added it's important for schools to offer more mental health support and interventions to help students cope with depression and low self-esteem.

Pabayo and Benny said this is particularly important during the COVID-19 pandemic, when income inequality levels are rising, with many lower-paid workers losing their jobs or having reduced working hours while higher-income employees who work at home continue to thrive financially.

"With COVID-19, we're going to see even more problems because COVID has worsened mental health, but it has also worsened the income gaps," said Benny.