Simple signs of inflammation linked to depression
Children with high levels of chemicals linked to inflammation in their blood are more likely to get mental illnesses as they get older, a study suggests. If confirmed, this finding might one day lead to new ways to prevent or treat these illnesses.
BMJ Group News
What do we know already?
Doctors have known for a long time that inflammation ( swelling), especially of the blood vessels, is linked to serious illnesses including heart disease and diabetes. We also know that people who have these conditions are more likely than people without them to have depression.
When someone has an illness that involves inflammation, such as an infection or heart disease, levels of certain chemicals in the blood are much higher than normal. Some recent studies have found that people with some mental illnesses may also have higher levels of these chemicals. But these studies haven’t been able to tell us enough to establish a link.
Now researchers in the UK have looked at whether children with high levels in their blood of two chemicals linked to inflammation (called IL-6 and CRP for short) might be more likely to have mental illnesses later in life.
How was the new study done?
The researchers tested the levels of IL-6 and CRP in the blood of about 4,500 9-year-olds who had no signs of mental illnesses. They followed up with the children nine years later, when they were 18 years old. They then looked at whether the children whose IL-6 and CRP levels had been high at the start of the study were more likely to have had problems with mental illness since the original blood test.
What does the new study say?
Children with the highest levels of IL-6 at the start of the study were more likely than those with the lowest levels to have had problems with mental illnesses in the nine years that the study lasted.
The children with high levels of these chemicals were about 50 percent more likely to have depression at age 18 and more than twice as likely to have an illness called psychotic disorder.
The researchers did not find a similar link between these illnesses and higher levels of CRP.
How reliable is the research?
In this study the researchers were careful to adjust their results to take account of things that could have skewed them, such as the children’s weight, social class, and whether their mother had had depression after giving birth (post-natal depression).
But there are reasons for caution about these findings. One problem was that the researchers only managed to follow up with about half of the children who took the original blood test. So the study was a lot smaller than the researchers had originally hoped, which means that its results carry less weight.
What does this mean for me?
These findings suggest that children with high levels of chemicals linked to inflammation may be more likely to have mental health problems later in life. For a scientist, the next logical step is to look at whether reducing levels of these chemicals might help prevent or treat mental illness.
From the way this study has been reported in the media, though, you’d be forgiven for thinking that you might treat mental illness simply by taking pills that relieve inflammation, such as aspirin or ibuprofen. But the reality is nowhere near that simple - and you should not try to use these medicines to treat mental illness.
It’s possible that, in time, the results of studies like this one might lead to new ways to prevent and treat mental illness. For now, though, if you think you may have mental health problems there are already treatments that can help. You can talk to your doctor to find the help that is best for you.