Researchers uncover the link between sickness and depression

According to a new study led by researchers at Northeastern University, the risk of depression in adolescents may be related to psychological trauma suffered in childhood. Also, it seems that the stress suffered in the past has influences on not only on mental health but also on the immune system. Heather Brenhouse, an assistant professor of psychology at Northeastern University, explained that those who have suffered childhood trauma and adversity have higher levels of inflammatory markers in the blood. The immune system and nervous system lie in close connection, according to Brenhouse. “We’re trying to figure out how early life stress, in particular, changes the development of the immune system and how that winds up leading to neuroinflammation later on,”she said.

The researchers explained that most of the emotional experiences from childhood are manifested only in adolescence. However, if those markers of inflammation are present before symptoms appear, doctors may use these markers to predict future mental illness. Now the investigators from Northeastern University have been conducting experiments on animals to see if these inflammatory biomarkers are present in rats that suffered trauma in early life. Also, they are trying to uncover the mechanism through which this inflammation leads to impaired neuronal circuits in depression. By understanding these mechanisms and connections, they could develop new therapeutic strategies to treat certain mental diseases.

In their new study, the researchers are going to take blood samples to measure the level of different cytokines (molecules that are released in an immune reaction) in various stages of childhood. During this time, children will be monitored closely to see if they develop symptoms or signs of cognitive dysfunction in adolescence. Also, researchers want to analyze how early life stress affects neural circuits in these adolescents.

In addition, the study will indicate if certain receptors are involved in these cognitive dysfunctions. Researchers are particularly interested to see what exactly is the role of NR2A, a neurotransmitter receptor in the prefrontal cortex. It must be said that this type of receptor binds glutamate, a neurotransmitter involved in diseases such as schizophrenia. Laboratory experiments have shown that animals who have suffered mental stress in early life have higher levels of NR2As. Brenhouse said that they know that this receptor is upregulated, but they still do not know yet if it is important. She added that the next step is to determine whether blocking inflammation leads to changes in the function of these receptors.