Mitochondria May Hold Keys to Anxiety and Mental Health

Carmen Sandi recalls the skepticism she faced at first. A behavioral neuroscientist at the Swiss Federal Institute of Technology in Lausanne, she had followed a hunch that something going on inside critical neural circuits could explain anxious behavior, something beyond brain cells and the synaptic connections between them. The experiments she began in 2013 showed that neurons involved in anxiety-related behaviors showed abnormalities: Their mitochondria, the organelles often described as cellular power plants, didn’t work well — they produced curiously low levels of energy.

Those results suggested that mitochondria might be involved in stress-related symptoms in the animals. But that idea ran contrary to the “synapto-centric” vision of the brain held by many neuroscientists at the time. Her colleagues found it hard to believe Sandi’s evidence that in anxious individuals — at least in rats — mitochondria inside key neurons might be important.

“Whenever I presented the data, they told me, ‘It’s very interesting, but you got it wrong,’” Sandi said.

Yet a growing number of scientists have joined her during the past decade or so in wondering whether mitochondria might be fundamental not just to our general physical well-being but specifically to our mental health. In particular, they have explored whether mitochondria affect how we respond to stress and conditions like anxiety and depression. 

Although much of the evidence so far is preliminary, it points to a substantial connection. Mitochondria seem to be central to the very existence of a stress response, serving both as mediators of it and targets for the damage it can do. To some of the researchers involved in this work, the stress response even looks like a kind of coordinated action by mitochondria throughout the body that interacts with the neurological processing.