Childhood Depression and Heart Disease

Donald Lloyd-Jones, M.D., does not mince words about where American kids are headed. "Their future is bleak," he says. As chair and associate professor of preventive medicine at Northwestern University's Feinberg School of Medicine, and a physician at Northwestern Memorial Hospital, he has been tracking a pattern that alarms him: adolescents, roughly ages 12 to 19, now face a higher likelihood of dying from heart disease at a young age than today's adults do. That conclusion came out of his team's analysis of teen health data pulled from the 2003 through 2008 National Health and Nutrition Examination Surveys.

The survey participants gave blood samples here and there and sat for physicals that logged blood pressure, weight, and height. Out of 5,547 of them, not a single person qualified as having optimal heart health. The American Heart Association frames cardiovascular health around seven measures, one of which is maintaining a healthy weight and Body Mass Index.

The numbers from the bloodwork and questionnaires were grim. None of the diets reported hit the mark for healthy eating. Around 80 percent of participants ate poorly, loading up on sodium and sugar. Most of these kids and teens barely moved: only 38 percent of girls and 52 percent of boys hit a good level of physical activity. Put bad food and a sedentary routine together and the rest of the heart-health factors slid downhill too.

One major risk the surveys, blood tests, and physicals left out was depression. Physical health predicts heart trouble, true, but there is solid evidence tying depression to a worsening of the other risks. Research has repeatedly shown that teenagers who were depressed as children are more prone to smoking, to carrying extra weight, and to sitting still. The part that stings is that these habits tend to stick around even after the depression itself lifts. Depressive symptoms in childhood seem to leave a mark that outlasts recovery.

There is more. Depressed children carry a raised risk of developing cardiac disease, and not only decades later as adults. It can show up in the teenage years. For a long time researchers could not pin down how the timing of depression related to heart problems. Then a joint effort by scientists at the University of South Florida, Washington University in St. Louis, and the University of Pittsburgh pointed to something specific: childhood depression not only raises the later risk of heart disease, it appears to speed up when the trouble arrives.

Robert M. Carney, Ph.D., a professor of psychiatry at Washington University and one of the authors, explained why that bothers him. "Part of the reason this is so worrisome is that a number of recent studies have shown that when adolescents have these cardiac risk factors, they're much more likely to develop heart disease as adults and even to have a shorter lifespan," he said. Consider smoking: people who smoked as teenagers are twice as likely to die by age 55 compared with those who never picked up the habit. Obesity and the other risks carry comparable penalties.

The researchers turned up another thread involving the parents. Mothers and fathers of teens who had been depressed as children showed higher rates of heart disease themselves. To tease apart how much of this is genetic, the team's 2011 survey circled back to people who had taken part in a 2004 study. Those participants had been 16 at the time and reported on their weight, smoking, and activity. Three groups made up the sample: more than 200 children with a history of depression, roughly 200 of their siblings, and about 150 unrelated children matched on age and sex who had no depression history.

What they found cut through the genetics question. Setting aside family lines and whether the depression was still present, early-onset depression stood out as the single biggest predictor of the behaviors that lead to heart disease. Obesity, smoking, and inactivity all climbed in the group that had been depressed as children. And this held even though only 15 percent of those teenagers were still dealing with depression by the time of the follow-up.

"Depression seems to come first," Carney said. "It's playing an important, if not a causal, role." He is careful to note that genetics feed into both depression and heart disease. Still, head to head, the children with depression showed riskier patterns for their hearts than their own siblings did. Carney and his colleagues want more study done, but their current reading is plain enough: catching and treating depression early should rank near the top of the list for doctors, mental health professionals, and parents.

Depression in children often does not look the way it does in adults, which makes it easy to miss. Caregivers are advised to get help when a child shows warning signs that start interfering with daily life. Those listed here are only a handful of the possible signals. Watch for sharp swings in mood or energy, and treat any talk of suicide, or of hurting themselves or other people, as serious.

- Melissa Lavery, M.S.