The current state of the neurogenic theory of depression. The lesion may comprise deficiencies in the absolute concentrations of norepinephrine andor. Blue genes and the monoamine hypothesis of depression. 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. What is the mode of action for monoamine oxidase inhibitors maois. These theories achieved broad popularity in the mid1960s. Both the maois and tcas remedy this situation, although they do so in different ways. Monoamine theory of depression exposed as incomplete, simplistic.
Child depression, mood disorder, mania, bipolar disorder. The monoamine theory of depression is based on the fact that. 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. 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. The monoamine theory of depression is based on the fact. A 26yrold woman receiving phenelzine 15 mg 6hourly for depression consumed 60 ml of.
The monoamine hypothesis of depression predicts an impairment in central monoaminergic function. Scientific studies have found that different brain areas show altered activity in people with major. Monoamines a guide to monoamines and antidepressants, maoi. 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. The symptoms of depression can be improved by agents that act by various mechanisms to increase synaptic concentrations of monoamines. Depression may be caused by a stressinduced deficiency in monoaminergic activation of genes that code for neurotrophic factors. Learn vocabulary, terms, and more with flashcards, games, and other study tools. 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.
The oxford english dictionary defines depression as a mental condition. The main limitation for the monoamine hypothesis of depression is the therapeutic lag between initiation of antidepressant treatment and perceived improvement of symptoms. 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. The monoamine theory of depression established that depression was due to. History and evolution of the monoamine theory of depression. The serotonin theory of depression 5 the reason for th e discrepancies between regions are unknown. Monoamine, in particular serotonergic neurotransmission has long been recognized as an important factor in the aetiology of depression. The media and the chemical imbalance theory of depression.
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. Pathophysiology of depression and mechanisms of treatment. In primary care settings, as many as 30% of patients report depressive symptoms, but depression. What evidence supports this hypothesis as a cause of affective disorder. Pathophysiology of depression and mechanisms of treatment ncbi. After studying the material on this page you should be able to. 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. Depressive disorders occur at any age but typically develop during the mid teens, 20s, or 30s see also depressive disorders in children and adolescents. When a cell needs to transport a monoamine in or out of a cell, they use a class of proteins called monoamine transporters. Norepinephrineserotonin agonists, and, finally ssris act as serotonin 5ht agonists. Most currently available antidepressants target monoamine neurotransmitter function. 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. 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. Alleged divisions between west european and us researchers over.
By contrast, the monoamine theory of antidepression is alive and kicking. Hall, 1998 pharmacological pharmacological treatment often makes up a big part of the treatment regimen for persons suffering from major depression. The highs and lows of the serotonin theory of depression. 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. There are an increasing number of articles even in the mainstream green journal american journal of psychiatry attesting to that. We thank dr cyril ndidi nwoye, a native english speaker and language. The main limitation for the monoamine hypothesis of depression is the therapeutic lag. 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 lesion may comprise deficiencies in the absolute concentrations of norepinephrine andor serotonin 5ht. Integrating the monoamine, neurotrophin and cytokine. The theory also transformed the pharmaceutical companies. Depletion studies have shown a correlation between such deficiencies and depressive symptoms. Worldwide, depression is a major cause of disability and premature death.
Dextromethorphan cosylan, like pethidine, blocks neuronal 5ht uptake. Review the full course description and key learning outcomes and create an account and enrol if you want a free statement of participation. These feelings often go away with time and you feel better. The monoamine hypothesis of depression states that a depletion of neurotransmitters, known as monoamines, within the brain leads to depression. Some studies have found abnormally high numbers of serotonin receptors in the prefrontal cortex in. Monoamine oxidase inhibitors and anaesthesia 225 respiratory depression may require assisted ventilation. Pdf the serotonin 5ht hypothesis of depression has played an important role. Jun 15, 2016 cartoonish, simplified monoamine theory of depression kierra van rootselaar. List the two main types of depression and define each endogenous depression is a serious depression that usually requires psychotherapy and drug treatment. Cartoonish, simplified monoamine theory of depression kierra van rootselaar. In molecular and cellular theory, stress, depression, and the mechanism of antidepressant.
Evolution of the monoamine hypothesis of depression 2019. Cartoonish, simplified monoamine theory of depression youtube. 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. Bipolar disorder and depression in childhood and adolescence. If these feelings are severe or affect your everyday life for more than 2 weeks, see your doctor. Because all theories of depression apply to only some types of depressed. Major depressive disorder mdd, also known simply as depression, is a mental disorder. 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 monoamine theory of mental depression states that mental depression is caused by low brain levels of norepinephrine and serotonin.
In different cultures some complain of excessive headaches and extreme pain and this is identified as depression, moderate or otherwise. 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. 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. Signs lose interest in things that you enjoy feel restless. This depletion may be related to a lack of neurotransmitters or some other fault. Pdf efficacy of the unified protocol for the treatment. The monoamine hypothesis posits that depression is caused by decreased monoamine function in the brain. People who may have had depression include english author mary shelley. 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. 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. The monoamine hypothesis of depression predicts that the underlying pathophysiologic basis of depression is a depletion in the levels of serotonin. T2 a modulatory role for monoamines, based on new findings from monoamine depletion experiments in humans.
The monoamine theory, derived from the efficacy of monoaminergic drugs in treating. 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. 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. Depression symptoms, causes, medications and therapies. The catecholamine theory of depression fly fishing devon. Monoamines are neurotransmitters that include serotonin, dopamine, norepinephrine, and epinephrine monoamine hypothesis of depression. 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. Other evidence supporting the monoamine hypothesis comes from postmortem studies of the brains of depressed people who unfortunately committed suicide. 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. When a cell needs to transport a monoamine in or out of a cell, they use a class of proteins called monoamine transport. Request the article directly from the author on researchgate. E both a and d 9 severe ongoing neural degeneration is. History and evolution of the monoamine hypothesis of depression.
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. D most drugs effective in the treatment of depression are monoamine antagonists. B most drugs effective in the treatment of depression are monoamine agonists. 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. 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. Just as with schizophrenia, the history of the discovery and evolution of antidepression drugs is quite interesting.
Knocking the monoamine theory from the center stage of depression has marked a fundamental change in the field of psychology, and. Al qahtani a, department of psychiatry, imam abdulrahman bin faisal university, dammam, kingdom of saudi arabia, tel. Depression is the most common of the affective disorders. Blue genes and the monoamine hypothesis of depression stephen m. Cartoonish, simplified monoamine theory of depression. 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. For example, people with major depressive disorder may also have fewer monoamine nerve receptors, or possibly less. Monoamine theories associate depression with reduced brain monoamine levels. Since the introduction of the monoamine oxidase inhibitors maois and the first tca. Preclinical and clinical studies have demonstrated that zinc possesses antidepressant properties and that it may augment the therapy with conventional, that is, monoaminebased, antidepressants. Monoamine theory of depression exposed as incomplete. Depression not only involves the mind, it also involves the body and thoughts.
1171 1297 842 655 315 1484 1077 1304 572 946 1442 982 628 1514 494 307 310 1329 32 981 208 1008 1153 623 1265 351 1220 112 1451 186 551 712 1433 431 1269 558 918