Researchers have noted differences in the brains of people who are depressed as compared to people who are not. For instance, the hippocampus, a small part of the brain that is vital to the storage of memories, appears to be smaller in people with a history of depression than in those who've never been depressed. A smaller hippocampus has fewer serotonin receptors. Serotonin is a calming brain chemical known as a neurotransmitter that allows communication between nerves in the brain and the body. It's also thought that the neurotransmitter norepinephrine may be involved in depression.
One thing is certain -- depression is a complex illness with many contributing factors. The latest scans and studies of brain chemistry that show the effects of antidepressants help broaden our understanding of the biochemical processes involved in depression. As scientists gain a better understanding of the cause(s) of depression, health professionals will be able to make better "tailored" diagnoses and, in turn, prescribe more effective treatment plans.
Originally posted by zerbot565
hmm lets see ,
fear triggers hormones from the small part in the back center of brain thalamus that over rides you and you do thing s automaticly ,
constant fear mongering keeps hormone factory in over drive resulting in "mild brain damage" ^^cough cough^^^
outside stimulus makes you sad in the long run , mmkay
Originally posted by zerbot565
reply to post by Hefficide
now im depressed,
Enlargement of the thalamus provides an anatomical basis for why people who inherit two SERT-ss alleles are more vulnerable to major depression, posttraumatic stress disorder, and suicide.
edit on 7-11-2010 by zerbot565 because: link fix
The elevated number of pulvinar neurons in subjects with a SERT-ss genotype may serve to enhance subcortical input of emotionally relevant stimuli to the limbic system, providing a mechanism for the 5HTTLPR genetic variant to affect predisposition to conditions such as major depression.
The neurotransmitters responsible for these amazing feelings are serotonin, dopamine, norepinephine, melatonin, and oxytocin. Amino acids (proteins) responsible for their upkeep are trytophan and tyrosine, and enzymes in general.
To start off with, the serotonin theory of depression actually began as the norepinephrine theory of depression. This idea came from Dr. Schildkraut in 1965, who came up the with theory based on the pharmacotherapies current at the time. Antidepressant drugs were really new stuff then, and the original drugs, the tricyclic antidepressants, inhibited the reuptake of both serotonin and norepinephrine. So the norepinephrine theory wasn't that out there. The serotonin theory followed from Dr. Coppen in 1967, who hypothesized that serotonin, not norepinephrine, was the cause of antidepressant effectiveness. And as more drugs were discovered, he appeared to be right. First came the tricyclics, then the MAOIs, both of which had effects on serotonin. Then came the SSRIs, which had effects on almost nothing BUT serotonin, and were still effective as antidepressants. And yet, they're not THAT effective...
So depression MUST be caused by low levels of serotonin in the brain, right? Wrong! Just because a drug relieves the symptoms of something, does not mean that the lack of that drug was the cause of the symptoms. In the most common example, it's a well known fact that headaches are not caused by a lack of asprin...
So basically, there aren't large numbers of studies out there saying "serotonin theory of depression totally works!", and there are other drugs which work for depression, and yet exclude the serotonin system all together. But Prozac still works in a significant number of patients. So what does this mean? Is the serotonin theory of depression totally wrong? Well, probably not entirely. The brain is a complicated place, and it's most likely that depression is a combination of factors, such as changes in neuronal growth and death, changes in neuronal connections, and changes in the biochemistry of neurotransmitters such as serotonin. Additionally, it is very possible that all of these changes feed back and influence each other. So serotonin may still play a role in depression, but it is probably not the main cause, and in fact there may not be one main cause of depression.