Numerous researches have emerged that serotonin is being linked to depression. One study emerged however that there is no such thing as serotonin deficiency. As per Medical News Today, theorists claimed that increasing levels of serotonin is vital for treating depression. As per the website this approach in treating depression is known by the anti-depressant Prozac. Prozac boosts serotonin levels, which makes it popular in treating depression.

Because of Prozac's popularity the theory that low levels of serotonin caused depression became popular

A chairman of pharmacology department at the University of Texas Health Science at San Antonio, Alan Frazer told NPR in a 2012 feature on the serotonin theory.

"I don't think there's any convincing body of data that anybody has ever found that depression is associated to a significant extent with a loss of serotonin."

A professor of neuroscience at Harvard University in Boston, MA, Dr Joseph Coyle stated that:

"Chemical imbalance is sort of last-century thinking. It's much more complicated than that. It's really an outmoded way of thinking."

As per recent studies, it revealed that 60-70% of depressed individuals no longer respond to Prozac or similar drugs. In line with these results, researchers from John D. Dingell VA Medical Center and Wayne State University School of Medicine wanted to get a further look in the correlation of depression and serotonin.

The medical team then developed mice that lacked the ability to produce serotonin and used numerous tests to investigate whether the mice would be able to exhibit depression symptoms. To their surprise, the mice that went the research only displayed high levels of compulsive and aggression but did not display any depression symptoms. As a result of the study, the researchers were able to conclude that serotonin may not be a dominant factor in depression.

For additional details regarding depression and its correlation to serotonin you can check the Web Md.