A stressful year\u00a0leads to\u00a0anxiety.\u00a0Lasting\u00a0isolation\u00a0gives way to\u00a0depression.\u00a0An old trauma\u00a0nags\u00a0until it\u00a0becomes\u00a0paralyzing.\u00a0Psychological and social experiences shape the brain, potentially leading to\u00a0mental health\u00a0issues. But the underlying mechanisms-how these experiences translate to physiological changes in the\u00a0brain-remain poorly understood.\u00a0<\/p>\n
Now, psychological scientists may have found a missing link.\u00a0<\/p>\n
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We actually have biomarkers that really are showing links between psychological processes and people’s physiology.”<\/p>\n
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Christopher\u00a0Fagundes, professor of psychological sciences, Rice\u00a0University<\/p>\n
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In a\u00a0review published in\u00a0Current Directions in Psychological Science,\u00a0Fagundes\u00a0and his colleagues\u00a0argue that the missing link might be mitochondria-those bean-shaped organelles from high school biology class.\u00a0<\/p>\n
Mitochondria are best known as the powerhouses of the cell for their role in generating energy. But they are now being recognized for many more roles,\u00a0including\u00a0their part\u00a0in immune signaling, stress responses, and neural functioning.\u00a0They are sensitive to environmental changes and social conditions, suggesting stress,\u00a0loneliness, and\u00a0trauma\u00a0may target mitochondria, leading to downstream psychological effects. Alterations in mitochondrial function have been linked to anxiety, depression, post-traumatic stress disorder\u00a0(PTSD), Alzheimer’s disease, and\u00a0other neurological disorders, as well as physical health outcomes such as cardiovascular diseases, diabetes, and certain cancers.\u00a0<\/p>\n
“The\u00a0actual cellular machinery that links these experiences to disease really starts\u00a0at the level of the mitochondria,” said\u00a0Fagundes, in an interview with the\u00a0Observer.\u00a0“Everything from the things we think of in terms of oxidative\u00a0stress,\u00a0to fatigue\u00a0we feel,\u00a0to the byproducts that come when stressors get out of control, it really is at the root of that.”\u00a0<\/p>\n
The brain’s high energy demand makes it particularly vulnerable to mitochondrial dysfunction. If mitochondria are less efficient, there is less energy for neurotransmission and plasticity, affecting processes that support mood regulation and\u00a0memory.\u00a0Variations\u00a0in mitochondrial DNA-which helps control mitochondrial function-are associated with a greater risk\u00a0for\u00a0anxiety and depression.\u00a0<\/p>\n
Mitochondria may also be the link between stress, inflammation<\/a>, and a number of mental health and cognitive disorders.\u00a0Chronic\u00a0stress\u00a0gradually reduces mitochondrial efficiency, leading to disrupted energy balance, increased inflammation, and impaired brain signaling, which may help explain how stress can lead to fatigue, cognitive difficulties, and mood disturbances. Differences in mitochondrial function may also help explain why some people are more vulnerable to stress than others.\u00a0<\/p>\n “A lot of the relationships that we’ve been thinking of-[between]\u00a0inflammatory processes and these kinds\u00a0of mental health outcomes-we should look toward alterations in mitochondria being a real mediator\u00a0or\u00a0[underlying]\u00a0mechanism,” said\u00a0Fagundes.\u00a0<\/p>\n The good news is that mitochondria are not only vulnerable to stressors but may be responsive to interventions that\u00a0promote mitochondria resilience.\u00a0If mitochondria are at the heart of this feedback loop, increasing their efficiency may help increase energy, reduce inflammation, and improve brain signaling.\u00a0<\/p>\n Exercise, particularly endurance training, has the strongest and most consistent evidence for improving mitochondrial function.\u00a0Aerobic exercise improves mitochondrial enzyme activity\u00a0and mitochondrial number\u00a0and may be one pathway linking exercise to improved mental and physical health\u00a0(San-Mill\u00e1n, 2023).\u00a0<\/p>\n Other interventions show potential.\u00a0An intensive mindfulness program\u00a0reduced anxiety and altered mitochondrial activity, but other stress markers remained unchanged\u00a0(Gomutbutra\u00a0et al., 2022). Psychotherapy<\/a> increased\u00a0mitochondria numbers\u00a0in patients with PTSD,\u00a0but\u00a0these changes\u00a0didn’t\u00a0correlate with symptom improvement\u00a0(Hummel\u00a0et al., 2023).\u00a0Although mindfulness and psychotherapy may improve mitochondrial\u00a0function, more studies are needed to\u00a0support\u00a0these preliminary results.\u00a0<\/p>\n Combatting loneliness\u00a0may also be a potential target to improve mitochondria and stave off other diseases.\u00a0<\/p>\n “When people are lonely and socially isolated, a lot of times there seems to be this loop where then they have more anxiety to go\u00a0out of the house,” said\u00a0Fagundes. “That is a recipe for negative alterations in the mitochondria,\u00a0less energy, less resources to\u00a0expend.\u00a0So,\u00a0when\u00a0one\u00a0does try to break that cycle,\u00a0it’s\u00a0much more difficult.”\u00a0<\/p>\n As of now, few studies have examined the effects of improving social support on mitochondrial function.\u00a0More research into this and other ways to improve mitochondria resilience-and the various roles mitochondria play in the brain-may be the key to better understanding and\u00a0developing\u00a0better treatment for a variety of mental and physical disorders.\u00a0<\/p>\n As a field,\u00a0“We’ve been talking a lot about things like inflammation. It tells us something is happening, but mitochondria help\u00a0us explain why\u00a0it’s\u00a0happening at the cellular level,” said\u00a0Fagundes. “If we focus more at the cellular level, we’ll have a much deeper understanding of underlying processes.”\u00a0<\/p>\n Source:<\/p>\n Association for Psychological Science<\/a><\/p>\n Journal reference:<\/p>\n