Institute of Psychological Sciences, The University of Leeds, Leeds LS2 9JT, United Kingdom.
Med Hypotheses. 2010 Apr;74(4):735-40. doi: 10.1016/j.mehy.2009.10.026.
Currently available antidepressant treatments are no longer seen as the panaceas they once were. Only a proportion of the depressed population respond to them, they have a high relapse rate and a therapeutic lag of several weeks. The notable lack of progress in developing more efficacious drug-based antidepressant therapies over the past half century is a clear signal for the need to adopt new approaches. The current manuscript outlines the proposal that depression is an evolutionary adaptation that emerged where displaced dominants needed to make a transition to lower social status and that is now triggered, in those individuals that have this adaptation, by damage to reproductive potential from any source. The behavioural cluster associated with depression includes adoption of a hunched posture, avoidance of eye contact, loss of appetite for food and sex and sleep disruption. This behavioural cluster serves to reduce an individuals' attack provoking stimuli and so facilitates this social change. When viewed in this context, it becomes clear that many of the brain areas that mediate these behaviours (e.g. the pineal, hypothalamus and amygdala, whose main output, the stria terminalis passes through) all lie in close physical proximity to the third ventricle. In consequence, it is proposed that depression has its origins within this ventricle. Disruption of circadian rhythms, appetite for sex and food and fear/defence responses would all ensue if structures that border the third ventricle, or whose main connections pass through it, were damaged. Therefore, it is hypothesised that the behavioural expression of this adaptation is mediated by a single or pulsatile release of a yet to be identified noxious factor into the ventricular space. This extreme response reflects the severity of the emergency that was faced by our ancestral stock in this situation and has parallels with the development of other adaptations where the preservation of life (and hence the chance for further reproductive opportunities) takes precedence over all other concerns. The increased volumetric changes seen in the third ventricles of depressives and changes in other closely associated structures are in keeping with predictions based on the current hypothesis and it is hoped that this will be of heuristic value in the search for more effective drug-based antidepressant therapies.
目前可用的抗抑郁治疗方法已不再被视为昔日的灵丹妙药。只有一部分抑郁症患者对它们有反应，它们的复发率很高，而且治疗效果需要数周时间才能显现。在过去半个世纪中，在开发更有效的基于药物的抗抑郁治疗方法方面几乎没有取得进展，这清楚地表明需要采用新方法。本文概述了这样一种观点，即抑郁症是一种进化适应，它出现在需要从较高社会地位过渡到较低社会地位的被取代的主导者身上，而现在，由于任何来源对生殖潜力的损害，这种适应在那些有这种适应的个体中被触发。与抑郁症相关的行为特征包括采取蜷缩的姿势、避免眼神接触、失去对食物和性的食欲以及睡眠中断。这种行为特征有助于减少个体的挑衅刺激，从而促进这种社会变化。从这个角度来看，很明显，介导这些行为的许多大脑区域（例如松果体、下丘脑和杏仁核，其主要输出物终纹穿过）都位于第三脑室附近。因此，有人提出，抑郁症起源于这个脑室。如果第三脑室边缘的结构或其主要连接穿过的结构受损，那么昼夜节律紊乱、对性和食物的食欲以及恐惧/防御反应都会随之而来。因此，假设这种适应的行为表达是由一种尚未确定的有害因子单一或脉冲式释放到脑室空间介导的。这种极端反应反映了我们的祖先在这种情况下所面临的紧急情况的严重性，与其他适应的发展有相似之处，在其他适应中，生命的保存（从而有更多的生殖机会）优先于所有其他考虑。抑郁症患者第三脑室体积的变化和其他密切相关结构的变化与当前假设的预测一致，希望这将对寻找更有效的基于药物的抗抑郁治疗方法具有启发价值。
