The study was reported in the New England Journal of Medicine (Olshan 62-63). However, Dr. Elliot Gershon, chief of the psychogenetics section of the National Institute of Mental Health, argued this discovery to be invalid. He claims that if there was a link, doctors could examine parents and find out if their kids will have depression or not (Olshan 63). Further studies done on children in an orphanage showed that adopted children whose biological parents had depression were much more likely to get depression than the adopted children whose biological parents weren't diagnosed with depression (Silverstein 23). These studies seem to be convincing but lack enough evidence.
The second category of believed causes for depression is biological factors. Biological factors include chemical messengers, hormonal imbalances, missing cells, and vitamin deficiencies and are believed to be a major cause of depression due to chemicals controlling the brain's functions.
Many studies have found that major depression could be linked to the malfunction of neurotransmitters, also known as chemical messengers. Neurotransmitters, which send messages back and forth between the cells, determine how people act. A shortage of .
three neurotransmitters, norepinephrine, dopamine, and serotonin, has been linked to patients with depression. Countless suicides have been committed by people with low levels of serotonin. This statement is justified because serotonin is believed to keep humans from being a violent human. A lack or excess of norepinephrine is believed to be just as dangerous. Dr. William Potter, a chief of clinical pharmacology at NIMH, stated "Norepinephrine is a device for focusing in on stimuli from the environment. The depressed person suffers from characteristic distortions- for example, seeing criticism where there is none- because he's unable to take in and process information correctly" (Silverstein 23-24).