It is suggested that depression is caused by low activity of certain monoamine neurotransmitters - particularly noradrenaline, serotonin and to a lesser extent, dopamine. These act like chemical messengers in the nervous system and are known to be particularly active in the rewards and punishment areas of the brain. They help to regulate the hypothalamus, which is a crucial link between the nervous system and the endocrine system and is involved in sleep, appetite, sexuality and physical movement - some of the key areas affected in depressive disorders.Support for this comes from drug therapies:
- Tricyclics and MAOIs which increase the available amount of noradrenaline and 5HT in the brain which were found to be effective in alleviating the symptoms of depression.
- Depression is an unwanted side effect of reserpine, a drug used to treat high blood pressure, which also acts by depleting levels of noradrenaline. Similarly, antidepressants such as Prozac, which are effective in providing relief from depression works by increasing the availability of serotonin (but have negligible effects on noradrenaline).
It was thought that depression was caused by neurotransmitters but there are other effects the drugs have so we cannot be sure that it is the change in neurotransmitter levels that accounts for the effectiveness of the drug. A problem is tat they have an immediate effect on NTM levels but take several weeks to have an effect on mood.
Comments
No comments have yet been made