The Chemistry of Persistent Anxiety

by Jerry Kennard, Ph.D. Medical Reviewer

How is it that some people are burdened with the anxiety and memory of traumatic times while others seem able to brush them off? Part of the answer may lie in our own ability to produce a natural chemical substance called dynorphin.

Dynorphin is produced in the brain and spinal cord. Chemically, it has broadly similar properties to opiates such as opium and morphine, although chemical studies suggest it is at least six times more powerful. Our bodies appear to produce different types of dynorphin and these are involved in regulating emotion, motivation, the experience of pain and how we respond to stress.

Various studies show that the level of dynorphin in our body can have dramatically different effects. In some situations dynorphins can produce feelings of euphoria but in others can stimulate pain rather than relieving it. Some studies show that blocking dynorphin can reduce depression, yet high levels are linked with resistance to cocaine addiction, overeating and hyperthermia.

When it comes to persistent anxiety, scientists at the Universities of Bonn and Berlin, say if the brain produces too little dynorphin symptoms will not subside. The team of neuroscientists noted that people have natural variations in the dynorphin gene meaning different levels are produced in the brain.

Volunteers with lower gene activity for dynorphin were compared with those with higher activity in a stress experiment. During the experiment, volunteers wore computer glasses and were subjected variously to the appearance of blue and green squares. When green squares appeared an unpleasant stimulus to the back of the hand was applied user a laser. Stress reactions were observed by increased sweat on the skin.

As part of the experiment brain scans were taken. These revealed that volunteers in the low dynorphin group showed stress reactions for considerably longer than those in the high dynorphin group. The amygdala, an area of the brain that processes emotional content, was shown to remain active for longer in the low dynorphin group.

It also appears that 'forgetting' anxiety is an active process that involves different parts of the brain. Volunteers in the low dynorphin group appeared to have less 'coupling' of these areas, which could explain why they retain the memory and anxiety associated with trauma for much longer. The scientists believe dynorphin levels have an important role in this regard and hope their results will develop new treatment approaches for trauma patients.


Universität Bonn (2012, July 6). When anxiety won't go away. ScienceDaily. Retrieved July 26, 2012, from
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Jerry Kennard, Ph.D.
Meet Our Writer
Jerry Kennard, Ph.D.

Jerry Kennard, Ph.D., is a Chartered Psychologist and Associate Fellow of the British Psychological Society. Jerry’s work background is in mental health and, most recently, higher education. He is the author of various self-help books and is co-founder of