Stress-Induced Depression Is Real

Stress breeds depression. Anecdotally, we all know that's the case, but scientifically speaking it's been a hypothesis that has until now remained unproven. A new study, however, reveals that chronic stress affects us at the genetic level, in turn creating very real brain changes associated with depression.

A team of researchers from Yale University has been studying how rats react to chronic, unpredictable stress. To do that, they subjected a group of rats to food and play deprivation, isolated them from other rodents, and switched around their day-night cyles for three weeks. Eventually, the rats were left with little interest in food or enjoying a sweetened drink, and didn't swim when placed in water -- all signs of rodent depressions.

Then, the researchers focused on their gene activity. In particular, the team found that the neuritin gene -- also present in humans -- was much less active compared to the control population. Part of the depressed group of rodents responded well to antidepressants, quickly recovering. The same, however, was also true if the researchers stimulated production of neuritin by injecting the rats with a virus that triggered the gene's expression.

Perhaps most interesting is the fact that stimulating the production of neuritin also protected the rats from structural brain changes seen in mood disorders -- which can't be said of all antidepressants. Previous research has shown that depression causes shrinking of the hippocampus and general decline in neuron health, both of which were prevented by the promotion of neuritin production. The findings are published in PNAS.

The results add serious weight to the idea that stress can directly bring about depression. Perhaps most importantly, it offers hope for the production of future anti-depressants. Currently, only 30 per cent of people with stress-related mood disorders achieve full recovery when using existing anti-depressants -- and a neuritin-based approach could help boost that figure significantly. [PNAS via Science]

Image: Lichtmeister/Shutterstock

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    Interesting that the outcome touted here is the future of antidepressants. Surely the removal of the stressor is best? How quickly did the rats recover when the stressful situation was removed?

    A lot of stress comes from the perception of powerlessness and catastrophising, both of which are usually completely unfounded. Lighten up - it probably won't happen. See, felling better already!

    1) It is, in fact, widely acknowledged (and well supported) that stress interacts with biological vulnerability to predict the onset of mental illness. See "diathesis-stress model". It is used to explain the onset of schizophrenia, bipolar disorder, depression, and anxiety disorders.

    2) These findings seem to point to the importance of evidence-based psychotherapy in depression treatment, not anti-depressants. Keep in mind that aside from the poor efficacy of antidepressants, they also have an incredibly high relapse rate in comparison to therapy, which has a prophylactic effect (i.e., therapy is more effective over the long term). Furthermore, therapy has been shown to change the patterns of activation in the brain in the same locations as anti-depressants, but when you finish therapy, the changes are maintained.

    3) This zeitgeist that depression = "neurotransmitter disorder" is scientifically invalid, and thankfully, it seems like the public are slowly catching on. If stress can predict the onset of mental illness, surely it follows logically that enhancing people's coping ability and addressing the way that they interact with their stressors (e.g., unhelpful thinking styles) is the crucial ingredient to competent depression treatment - not whether they take medication to change the biological consequences of stressors.

    If your house was falling apart at the foundations, would you simply plaster over the cracks and redecorate the interior?

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