History and evolution of the monoamine theory of depression. The monoamine hypothesis of depression states that a depletion of neurotransmitters, known as monoamines, within the brain leads to depression. In primary care settings, as many as 30% of patients report depressive symptoms, but depression. T2 a modulatory role for monoamines, based on new findings from monoamine depletion experiments in humans. The first major hypothesis of depression was formulated about 30 years ago and proposed that the main. Cartoonish, simplified monoamine theory of depression kierra van rootselaar. The lesion may comprise deficiencies in the absolute concentrations of norepinephrine andor. The serotonin theory of depression 5 the reason for th e discrepancies between regions are unknown.
Pathophysiology of depression and mechanisms of treatment ncbi. The monoamine hypothesis has been a major focus of research in depression for over 30 years and has led to the development of new classes of antidepressant drugs, such as ssris, selective noradrenergic reuptake inhibitors snris, and selective and reversible maois. After studying the material on this page you should be able to. The theory also transformed the pharmaceutical companies. The media and the chemical imbalance theory of depression. Norepinephrineserotonin agonists, and, finally ssris act as serotonin 5ht agonists.
Depression not only involves the mind, it also involves the body and thoughts. Bipolar disorder and depression in childhood and adolescence. It generally takes 23 weeks of chronic treatment before an antidepressant begins to have a clinical benefit, yet the drugs pharmacological effect for example, its inhibition of moa, or reuptake is immediate. Pdf the serotonin 5ht hypothesis of depression has played an important role. Learn vocabulary, terms, and more with flashcards, games, and other study tools. This finding led to the adoption of the monoamine hypothesis of depression, first put forward over 30 years ago, which proposes that the underlying biological or neuroanatomical basis for depression is a.
Request the article directly from the author on researchgate. The article by professor david healy, which appeared in the bmj, also said ssris had led to the marginalisation of cheaper and more effective treatments. We thank dr cyril ndidi nwoye, a native english speaker and language. Major depressive disorder mdd, also known simply as depression, is a mental disorder. Jun 15, 2016 cartoonish, simplified monoamine theory of depression kierra van rootselaar. In different cultures some complain of excessive headaches and extreme pain and this is identified as depression, moderate or otherwise. Signs lose interest in things that you enjoy feel restless. The highs and lows of the serotonin theory of depression. This depletion may be related to a lack of neurotransmitters or some other fault. The monoamine theory of depression established that depression was due to. Depression is not only a state of being sad, it is a disease that conquers the ability to feel emotion, whether good or bad, whatsoever. Although the monoamine theory still circulates in laymen conversation, modern science has largely discredited the simplistic idea, and is moving towards a more manyfactored, immunitycentric model of depression. Depression is the most common of the affective disorders.
There are an increasing number of articles even in the mainstream green journal american journal of psychiatry attesting to that. The monoamine theory of depression is based on the fact that. These feelings often go away with time and you feel better. D most drugs effective in the treatment of depression are monoamine antagonists. Depressive disorders occur at any age but typically develop during the mid teens, 20s, or 30s see also depressive disorders in children and adolescents. The oxford english dictionary defines depression as a mental condition. N2 the monoamine hypothesis of depression predicts that the underlying pathophysiologic basis of depression is a depletion in the levels of serotonin, norepinephrine, andor dopamine in the central nervous system. Monoamines a guide to monoamines and antidepressants, maoi. The catecholamine theory of depression fly fishing devon. There is plenty of evidence that ssris increase communication from neurones that release serotonin, as well as other monoamine transmitters, and that the ensuing downstream changes, such as creation of new neurons neurogenesis or modification of gene expression.
The fundamentals of mental health and mental illness pdf. What evidence supports this hypothesis as a cause of affective disorder. Alleged divisions between west european and us researchers over. Most currently available antidepressants target monoamine neurotransmitter function. A british medical journal editorial on serotonin and depression, which made the claim that newer ssri antidepressants are less effective than older tricyclic drugs, has been met with criticism from psychologists and psychiatrists.
The monoamine theory of depression is based on the fact. One explanation for this therapeutic lag is that the initial increase in synaptic serotonin is only temporary, as firing of serotonergic neurons in the dorsal raphe adapt via. One possible explanation is that brainst em levels may reflect changes at th e level ofserotonin cell bodies, whereas cortical measures indicate som e aspect ofte rminal activity in which basal levels are lowerby comparison. The hypothesis originated from early empirical clinical observations and has been generally recognized to mean that low concentrations of synaptic monoamines are a primary factor in the etiology of depression, other monoaminerelated disease. Drugs such as selective monoaminereuptake inhibitors, prozac, paxil, etc selective norepinephrinereuptake inhibitors, reboxetine and drugs that block the uptake of more than one monoamine neurotransmitter. The current state of the neurogenic theory of depression. Pathophysiology of depression and mechanisms of treatment. Depression was no longer seen as just a natural response to stress, there was now an underlying biological factor which was the cause of the depression. Monoamine theory of depression exposed as incomplete. Jul 21, 2016 the finding that depression is often associated with the short allele of the 5httlpr polymorphism has, sometimes, been touted as evidence against the monoamine hypothesis.
For example, people with major depressive disorder may also have fewer monoamine nerve receptors, or possibly less. Scientific studies have found that different brain areas show altered activity in people with major. Because all theories of depression apply to only some types of depressed. The main limitation for the monoamine hypothesis of depression is the therapeutic lag. People who may have had depression include english author mary shelley. Child depression, mood disorder, mania, bipolar disorder. Worldwide, depression is a major cause of disability and premature death. Blue genes and the monoamine hypothesis of depression. Besides the fact that antidepression drugs are all monoamine agonists, there is other evidence that supports the theory. The drugs developed out of the monoamine hypothesis for depression, which holds that depression is caused by insufficient activity of monoaminergic neurons carlson 1988, p. Depletion studies have shown a correlation between such deficiencies and depressive symptoms. List the two main types of depression and define each endogenous depression is a serious depression that usually requires psychotherapy and drug treatment. Monoamine theory of depression exposed as incomplete, simplistic. Hall, 1998 pharmacological pharmacological treatment often makes up a big part of the treatment regimen for persons suffering from major depression.
What is the mode of action for monoamine oxidase inhibitors maois. The monoamine theory of mental depression states that mental depression is caused by low brain levels of norepinephrine and serotonin. Preclinical and clinical studies have demonstrated that zinc possesses antidepressant properties and that it may augment the therapy with conventional, that is, monoamine based, antidepressants. In molecular and cellular theory, stress, depression, and the mechanism of antidepressant. Other evidence supporting the monoamine hypothesis comes from postmortem studies of the brains of depressed people who unfortunately committed suicide. The monoamine hypothesis of depression predicts an impairment in central monoaminergic function. Depression symptoms, causes, medications and therapies.
Some studies have found abnormally high numbers of serotonin receptors in the prefrontal cortex in. When a cell needs to transport a monoamine in or out of a cell, they use a class of proteins called monoamine transporters. Is this evidence for or against the monoamine hypothesis of depression significant time delay 23 weeks before antidepressant drugs start to show significant improvement in mood. The monoamine hypothesis posits that depression is caused by decreased monoamine function in the brain. Pdf efficacy of the unified protocol for the treatment. Integrating the monoamine, neurotrophin and cytokine. Review the full course description and key learning outcomes and create an account and enrol if you want a free statement of participation. These theories achieved broad popularity in the mid1960s. Cartoonish, simplified monoamine theory of depression. The lesion may comprise deficiencies in the absolute concentrations of norepinephrine andor serotonin 5ht. The serotonin transporter sert is the primary regulator of serotonin levels in the brain and a key target for widely used antidepressant drugs, such as selective serotonin reuptake inhibitors ssris.
Al qahtani a, department of psychiatry, imam abdulrahman bin faisal university, dammam, kingdom of saudi arabia, tel. Many antidepressant drugs acutely increase synaptic levels of the monoamine neurotransmitter, serotonin, but they may also enhance the levels of two other neurotransmitters, norepinephrine and dopamine. B most drugs effective in the treatment of depression are monoamine agonists. E both a and d 9 severe ongoing neural degeneration is. Monoamine theories associate depression with reduced brain monoamine levels. The hypothesis originated from early empirical clinical observations and has been generally recognized to mean that low concentrations of synaptic monoamines are a primary factor in the etiology of depression, other monoamine related disease. Both the maois and tcas remedy this situation, although they do so in different ways. A 26yrold woman receiving phenelzine 15 mg 6hourly for depression consumed 60 ml of. Figure 10 the monoamine hypothesis of mood disorders. Since the introduction of the monoamine oxidase inhibitors maois and the first tca. Monoamine, in particular serotonergic neurotransmission has long been recognized as an important factor in the aetiology of depression. Preclinical and clinical studies have demonstrated that zinc possesses antidepressant properties and that it may augment the therapy with conventional, that is, monoaminebased, antidepressants.
If these feelings are severe or affect your everyday life for more than 2 weeks, see your doctor. Knocking the monoamine theory from the center stage of depression has marked a fundamental change in the field of psychology, and. Just as with schizophrenia, the history of the discovery and evolution of antidepression drugs is quite interesting. History and evolution of the monoamine hypothesis of depression. Monoamine oxidase inhibitors and anaesthesia 225 respiratory depression may require assisted ventilation. When a cell needs to transport a monoamine in or out of a cell, they use a class of proteins called monoamine transport.
Furthermore, monoamine systems can function indirectly through their. The main limitation for the monoamine hypothesis of depression is the therapeutic lag between initiation of antidepressant treatment and perceived improvement of symptoms. In primary care settings, as many as 30% of patients report depressive symptoms, but feb 14, 2012 the monoamine hypothesis posits that depression is caused by decreased monoamine function in the brain. Monoamines are a group of organic compounds containing only one amino group several mood disorders are explained as due to either an excess or deficiency of monoamines. Depressive disorders msd manual professional edition. By contrast, the monoamine theory of antidepression is alive and kicking. An interesting historical correlate that comes to mind immediately is st johns wort hypericin thought for years to be an maoi, then found to inhibit the. The symptoms of depression can be improved by agents that act by various mechanisms to increase synaptic concentrations of monoamines. Efficacy of the unified protocol for the treatment of emotional disorders in the spanish public mental health system using a group format. The monoamine theory, derived from the efficacy of monoaminergic drugs in treating. Cartoonish, simplified monoamine theory of depression youtube. Evolution of the monoamine hypothesis of depression 2019. Monoamines are neurotransmitters that include serotonin, dopamine, norepinephrine, and epinephrine monoamine hypothesis of depression.
The earliest and probably most widely accepted scientific theory of antidepressant action is the monoamine hypothesis which can be traced back to the 1950s, which states that depression is due to an imbalance most often a deficiency of the monoamine neurotransmitters namely serotonin, norepinephrine and dopamine. Blue genes and the monoamine hypothesis of depression stephen m. The monoamine hypothesis, placebos and problems of theory. The monoamine hypothesis of depression predicts that the underlying pathophysiologic basis of depression is a depletion in the levels of serotonin. Apr 25, 2016 although the monoamine theory still circulates in laymen conversation, modern science has largely discredited the simplistic idea, and is moving towards a more manyfactored, immunitycentric model of depression. Dextromethorphan cosylan, like pethidine, blocks neuronal 5ht uptake.
1071 734 663 1514 1564 220 533 1504 597 1271 889 1517 438 1332 973 690 145 3 713 185 614 1337 1375 362 1055 1357 470 1493 388 438 1416 651 992 831 447