Stress associated with anxiety may physically alter the makeup of our mitochondrial cells, according to new research.

Chronic stress from major life events – such as the death of a loved one, divorce, unemployment, or war – can lead to panic attacks and anxiety disorder. An anxiety disorder is different from the occasional worry in that it is consistent and does not get better over time; excessive worry can cause both physical and emotional symptoms that may interfere with relationships and work or school. The National Institute of Mental Health notes that anxiety disorders are impacted by both genetic and environmental factors, including a stressful or traumatic experience.

But not everyone who experiences such an event develops an anxiety disorder, leading researchers and mental health experts to wonder what makes some people more resilient to stressors than others?

To help answer that question, researchers studied mice that developed symptoms of anxiety and depression, such as avoiding social interactions, after being exposed to high levels of stress. They then tracked changes in gene activity and protein production in a region of the brain that is responsible for stress and anxiety, including the prefrontal cortex, hippocampus, amygdala, and nucleus accumbens. In what they call a “cross-species multi-omics” approach, the science team analyzed the genes and proteins associated with mitochondrial cells and found a number of changes occurred in the mitochondria in the brain cells of mice exposed to stress compared with non-stressed mice. The researchers then tested blood samples from patients with panic disorder after having a panic attack and found similar mitochondrial changes.

“Our analyses revealed a consistent convergence of differentially expressed mitochondria-related pathways in the blood samples from panic disorder patients after exposure-induced panic attacks,” wrote the authors in PLOS Genetics, adding that cellular energy metabolism may be a common way that animals respond to stress.

Known as the “powerhouses of cells”, mitochondria turn what we eat into 90 percent of the chemical energy needed so that the body can live, as well as play a key role in making rogue cells die. According to the research, high levels of stress could affect how mitochondria function, resulting in broader implications to human health.

"Very little is known about how chronic stress may affect cellular energy metabolism and thereby influence anxiety symptoms," said author Iiris Hovatta, from the University of Helsinki, in a statement. "The underlying mechanisms may offer a key to new targets for therapeutic interventions of stress-related diseases."

Understanding the genetic makeup of those with anxiety, as well as its effects on the body, can help inform treatment options, which are currently limited mainly to psychotherapy and a variety of medications, according to WebMD.