Third ventricle hypothesis of depression: Difference between revisions
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[[File:Third ventricle.png|thumb|Third ventricle]] |
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==Background== |
==Background== |
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The Third Ventricle Hypothesis<ref>Hendrie CA, Pickles AR (2010) Depression as an Evolutionary Adaptation: Anatomical Organisation Around the Third Ventricle Medical Hypotheses 74: 735-740</ref><ref>Hendrie CA, Pickles AR (2010) Depression as an evolutionary adaptation: Implications for the development of new drug treatments. European Psychiatric Review 3:46</ref><ref>Hendrie CA, Pickles AR (2011) Depression: An evolutionary adaptation organised around the third ventricle In: Brinkworth M, Weinert F (eds) Darwinian Repercussions Darwinism in anInterdisciplinary Context Heidelberg, New York, London: Springer</ref><ref>Hendrie CA, Pickles AR (2012) The failure of the antidepressant drug discovery process is systemic J Psychopharm doi:10.1177/0269881112466185M |
The [http://www.academia.edu/1145735/Depression_An_Evolutionary_Adaptation_Organised_Around_the_Third_Ventricle Third Ventricle Hypothesis]<ref>Hendrie CA, Pickles AR (2010) Depression as an Evolutionary Adaptation: Anatomical Organisation Around the Third Ventricle Medical Hypotheses 74: 735-740</ref><ref>Hendrie CA, Pickles AR (2010) Depression as an evolutionary adaptation: Implications for the development of new drug treatments. European Psychiatric Review 3:46</ref><ref>Hendrie CA, Pickles AR (2011) Depression: An evolutionary adaptation organised around the third ventricle In: Brinkworth M, Weinert F (eds) Darwinian Repercussions Darwinism in anInterdisciplinary Context Heidelberg, New York, London: Springer</ref><ref>Hendrie CA, Pickles AR (2012) The failure of the antidepressant drug discovery process is systemic J Psychopharm doi:10.1177/0269881112466185M</ref> is a theory that describes [[Depression (mood)|depression]] from a behavioural perspective and considers that it developed as a response to the social emergency of members of our ancestral stock needing to remain in social groups that had become hostile to their presence. |
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Revision as of 18:42, 22 July 2013
Background
The Third Ventricle Hypothesis[1][2][3][4] is a theory that describes depression from a behavioural perspective and considers that it developed as a response to the social emergency of members of our ancestral stock needing to remain in social groups that had become hostile to their presence.
Ethological perspective
The behavioural cluster associated with depression includes hunched posture and avoidance of eye contact (which are primarily defensive), lack of appetites for food and sex (which reduce the need to compete for these resources) plus social withdrawal and sleep disturbance (which reduce the probability of engaging in potentially damaging social contact). This cluster together serves to reduce an individual’s attack provoking stimuli in a hostile social environment.
Evolutionary adaptation
Depression is not however a permanent state and is relieved, at least temporarily after a given period of time. Thus, individuals who managed to remain in their groups until after the social emergency had passed had at least some opportunity for further reproduction, no matter how slight and this provided the net gain in fertility (over those who did not remain in the group) necessary for this to become an evolutionary adaptation.
Depression is primarily seen in adults and often experienced following the loss of a child; break-up of a relationship; loss of a partner/spouse; death of a parent and/or the loss of a job (and the social status that goes with it). Hence, the theory holds that the key stimulus for triggering depression in those individuals that have this adaptation is ‘damage to reproductive potential’. Damage to reproductive potential is most clearly seen where there has been a transition from high social status that also confers reproductive advantage to lower social status where this reproductive advantage is lost.
Association with neuroanatomy
The Third Ventricle is implicated because the behaviours associated with depression can be related to structures that contact this ventricle. The hypothalamus lies at one end of the ventricle and this accounts for the effects on appetites for food and sex whilst the pineal lies at the other and has influence on circadian rhythms and sleep/wake cycles. Other behavioural symptoms of depression can be accounted for by effects of the amygdala and the hippocampus whose major pathways (stria terminalis and fornix) pass through the ventricle.
Proposed mechanism of action
The Third Ventricle Hypothesis proposes the behavioural cluster associated with depression is produced by the acute release of an unknown (probably cytokine) inflammatory agent into the ventricular space. This causes damage to those structures and pathways that contact the ventricle and it is this damage that produces the behavioural syndrome.
There are several lines of evidence that are in keeping with predictions based upon the theory although the Third Ventricle Hypothesis has yet to be directly tested experimentally. This evidence includes (a) findings that show depression to be associated with a cytokine mediated inflammatory event somewhere in the system[5][6][7][8] and (b) imaging studies revealing that the third ventricle is enlarged in depressives [9][10] indicating a damage-induced loss of volume in the structures surrounding it (See Hendrie & Pickles, 2010). The analogy proposed by Hendrie & Pickles (2010) is that of an explosion, where the damage produced is detectable long after the event that caused it has dissipated.
Related papers
Hendrie, C. A., & Pickles, A. R. (2009). Depression as an evolutionary adaptation: Implications for the development of preclinical models. Medical hypotheses, 72(3), 342-347
Hendrie, C.A., & Pickles, A.R., (2012). The failure of the antidepressant drug discovery process is systemic. Journal of Psychopharmacology DOI: 10.1177/0269881112466185
See also
References
- ^ Hendrie CA, Pickles AR (2010) Depression as an Evolutionary Adaptation: Anatomical Organisation Around the Third Ventricle Medical Hypotheses 74: 735-740
- ^ Hendrie CA, Pickles AR (2010) Depression as an evolutionary adaptation: Implications for the development of new drug treatments. European Psychiatric Review 3:46
- ^ Hendrie CA, Pickles AR (2011) Depression: An evolutionary adaptation organised around the third ventricle In: Brinkworth M, Weinert F (eds) Darwinian Repercussions Darwinism in anInterdisciplinary Context Heidelberg, New York, London: Springer
- ^ Hendrie CA, Pickles AR (2012) The failure of the antidepressant drug discovery process is systemic J Psychopharm doi:10.1177/0269881112466185M
- ^ Miller, A. H., Maletic, V., & Raison, C. L. (2009). Inflammation and its discontents: the role of cytokines in the pathophysiology of major depression.Biological psychiatry, 65(9), 732-741.
- ^ Raison, C. L., Capuron, L., & Miller, A. H. (2006). Cytokines sing the blues: inflammation and the pathogenesis of depression. Trends in immunology, 27(1), 24-31
- ^ Rothwell, N. J. (2004). Cytokines‐killers in the brain?. The Journal of physiology, 514(1), 3-17
- ^ Anisman, H., & Merali, Z. (2002). Cytokines, stress, and depressive illness. Brain, behavior, and immunity, 16(5), 513-524
- ^ Baumann B, Bornschlegl C, Krell D, Bogerts B. Changes in CSF spaces differ in endogenous and neurotic depression A planimetric CT scan study. J Affect Dis 1997;45:179–88.
- ^ Cousins, D. A., Brian Moore, P., Watson, S., Harrison, L., Nicol Ferrier, I., Young, A. H., & Lloyd, A. J. (2010). Pituitary volume and third ventricle width in euthymic patients with bipolar disorder. Psychoneuroendocrinology, 35(7), 1074-1081