Stress, Anxiety and Depression: diverse findings from mice and stressed people

There is a lot of disagreement about anxiety and depression among professionals. Some argue that they are discrete categories. Others say that they tend to co-exist. There is disagreement about whether the anxiety that often accompanies chronic depression is a cause or effect of the illness.

Research in mice suggests that chronic stress as a precursor of anxiety may be a trigger for -- rather than a symptom of -- depression. People with depression typically have measurably higher levels of cortisol (stress-fighting, anti-inflammatory hormone), but researchers disagree whether this is a cause or effect of depression. The findings of the mouse research indicate that chronic exposure to cortisol may contribute to the development of depression.

The mice were acutely (24 hours) and chronically (17 to 18 days) dosed with their stress hormone. They mice were then given a common behavioural test for anxiety in animals: researchers measured how much time it took to leave a small dark enclosure for a brightly lit, open field. The research reports that the mice exposed to chronically raised levels of stress hormones were more hesitant less to explore their new environment and more fearful.

The research also indicates that the mice with chronic exposure responded with dulled reactions to being startled: an indication that their nervous system might be overwhelmed.

For me, this research fits in with the concept of allostasis. And the research casts an interesting light on recent reports that the people displaced by Hurricane Katrina are displaying higher rates of asthma, emotional and behavioural disorders. 37% of parents and guardians describe their health as fair or poor compared with 10% before the hurricane. More than half of the mothers and other female caregivers scored "very low" on a mental health screening exam: the score is consistent with clinical disorders like depression or anxiety.

Dr. Irwin Redlener, the director of the National Center for Disaster Preparedness at Mailman and co-founder of the Children's Health Fund, was interviewed about the physical and emotional problems reported by the children displaced by the hurricane.

Children do not have the ability to absorb six or nine months of high levels of stress and undiagnosed or untreated medical problems [without long-term consequences].

It will be interesting to see whether or not these studies will lead to a different understanding of stress, anxiety and depression. And whether there will be significant changes in treatment programmes.

Copyright 2006, Tony Plant Happystance Project