Fish research finds link between chronic stress, depression

Effexor users who have suspected that chronic stress is a cause of their depression may be right. Researchers at the Max Planck Institute of Neurobiology have recently found a link between high levels of stress hormones and anxious or depressed behavior in zebra fish.

In the study, published in the June 2013 edition of Molecular Psychiatry, researchers analyzed fish that lacked the glucocorticoid receptor, which regulates cortisol. When the hormone cortisol is released in high levels, it causes consistently elevated stress in humans and other animals. When placed in a new tank, the zebra fish with this genetic mutation showed extreme signs of depression and hyper-anxious behavior, such as sinking to the bottom of the tank and freezing. Typically, fish can appear a bit nervous when entering a new habitat, but they acclimate fairly quickly. The fish in this study took an excessively long time to adjust and, when tested, they had elevated concentrations of cortisol, CRH and CTH - all of which are stress hormones.

However, shortly after scientists added an antidepressant to the water, the behavior of the fish returned to normal. This is an important finding because it establishes a causal link between the malfunction or lack of a glucocorticoid receptor, elevated stress hormones and depression and anxiety. While researchers are not able to establish a causal link in human research, they can say that chronic stress is associated with depression. Additionally, the zebra fish research can provide insight into how antidepressants or anti-anxiety medications can work to reduce stress levels.

Chronic stress
Stress is the body's way of reacting to a positive or negative change in one's life - which can happen to just about everyone. Our bodies release stress hormones as part of a "fight or flight" reaction, and in some cases, stress can even be beneficial. For example, if it gets someone through a dangerous situation safely or gives them an extra boost to study and make it through a tough exam. However, it's necessary to find ways to cope with stress so that it doesn't become chronic, unmanageable or trigger anxiety or depression. Chronic stress, anxiety and depression can cause relationships to suffer, interrupt one's daily routine and decrease productivity at work. Some people manage chronic stress by seeing a therapist, meditating, taking yoga classes or cutting back on their activities and obligations.