Stress, Brain Changes and Depression

You probably already know at an intuitive level that after feeling anxious and stressed for awhile, your mood tends to dip a bit. Maybe you’re just mildly dejected, or perhaps you develop a full-fledged depression.

Researchers at the University of Washington have recently discovered that a neuropeptide called corticotropin-releasing factor (CRF), which under normal conditions helps the brain to release dopamine, a hormone associated with pleasurable sensations, loses this ability under stressful conditions, for over three months. That’s a long time.

In the study, mice were put in one of two connected cages. In the first cage, an area of their brain called the nucleus accumbens was infused with CRF. The mice were then moved into the second cage, and their nucleus accumbens was infused with a placebo (inactive) substance. The mice were then left to pick their preferred cage, the hypothesis being that the mice would choose the cage where they experienced a dopamine surge (i.e., the cage where they received CRF). This was indeed the case.

Next, the mice were subjected to a stressful situation, in this case, being forced to swim in water many times over two days. The researchers found that after this stressor, the ability of CRF to boost the release of dopamine in the brains of the mice was abolished. Moreover, the mice actually wanted to spend less time in the cage where they received CRF, indicating that CRF was producing a distasteful effect, which lasted over 90 days.

So, if you’ve experienced a traumatic event that caused you significant stress, be aware that your body is going through some major biochemical changes. As a result, you may sink into depression — and possibly for an extended period of time. Be alert for symptoms such as decreased enjoyment of activities that you usually enjoy, less interest in socializing, and alterations in sleep and eating patterns.

Be patient with yourself, understand that your body needs time to heal — and make sure to reach out for support from family, friends, and mental health professionals, if needed. It’s hard to take action when it feels as if nothing will help — but this is the disorder talking, not the reality.

More information: Severe stress switches CRF action in the nucleus accumbens from appetitive to aversive, Nature (2012) doi:10.1038/nature11436