"You’ve seen it in television ads, read it in newspaper articles, maybe even heard it from your doctor: depression is caused by a chemical imbalance in the brain that medication can correct. According to the chemical imbalance theory, low levels of the brain chemical serotonin lead to depression and depression medication works by bringing serotonin levels back to normal.
However, the truth is that researchers know very little about how antidepressants work. There is no test that can measure the amount of serotonin in the living brain—no way to even know what a low or normal level of serotonin is, let alone show that depression medication fixes these levels.
While antidepressant drugs such as Prozac increase serotonin levels in the brain, this doesn’t mean that depression is caused by a serotonin shortage. After all, aspirin may cure a headache, but it doesn’t mean that headaches are caused by an aspirin deficiency. Furthermore, many studies contradict the chemical imbalance theory of depression.
Experiments have shown that lowering people’s serotonin levels doesn’t always lower mood, nor does it worsen symptoms in people who are already depressed. And while antidepressants raise serotonin levels within hours, it takes weeks before medication is able to relieve depression. If low serotonin caused depression, there wouldn’t be this antidepressant medication"
http://www.helpguide.org/mental/medications_depression.htmRead Jeffrey Lacasse in the journal published by the Public Library of Science:
"Serotonin and Depression: A Disconnect between the Advertisements and the Scientific Literature
Many ads for SSRI antidepressants claim that the drugs boost brain serotonin levels. Lacasse and Leo argue there is little scientific evidence to support this claim."
http://www.plosmedicine.org/article/info:doi/10.1371/journal.pmed.0020392or watch them on Youtube:
http://www.youtube.com/watch?v=sWE3UGl7KFkRead Peter Breggin:
"As earlier noted, the public has been subjected to a high-power selling campaign for psychiatric drugs. This campaign, conducted by drug companies and organized psychiatry, has convinced most people that psychiatric drugs are much safer and more valuable than they really are."
"Psychiatric drugs do not work by correcting anything wrong in the brain. We can be sure of this because such drugs affect animals and humans, as well as healthy people and diagnosed patients, in exactly the same way. There are no known biochemical imbalances and no tests for them. That's why psychiatrists do not draw blood or perform spinal taps to determine the presence of a biochemical imbalance in patients. They merely observe the patients and announce the existence of the imbalances. The purpose is to encourage patients to take drugs."
"Ironically, psychiatric drugs cause rather than cure biochemical imbalances in the brain. In fact, the only known biochemical imbalances in the brains of patients routinely seen by psychiatrists are brought about by the psychiatrists themselves through the prescription of mind-altering drugs."
Most especially read Eliot Valenstein, Blaming the Brain. He explains exactly how this "theory" was created and spun and forced upon the public.
Or read my paper which I'll send to anyone interested.