为什么有的人爱咬指甲？.doc

为什么有的人爱咬指甲？Why do we bite our nails?What do ex-British prime minster Gordon Brown, Jackie Onassis, Britney Spears and I all have in common? We all are (or were) nail biters.Its not a habit Im proud of. Its prettydisgustingfor other people to watch, ruins the appearance of my hands, is probably unhygienic and sometimes hurts if I take it too far. Ive tried to quit many times, but have never managed to keep it up.Lately Ive been wondering what makes someone an inveterate nail-biter like me. Are we weaker willed? More neurotic? Hungrier? Perhaps, somewhere in the annals of psychological research there could be an answer to my question, and maybe even hints about how to cure myself of this unsavoury habit.My first dip into the literature shows up the medical name for excessive nail biting: onychophagia. Psychiatrists classify it as an impulse control problem, alongside things like obsessive compulsive disorder. But this is for extreme cases, wherepsychiatrichelp is beneficial, as with other excessive grooming habits like skin picking or hair pulling. Im not at that stage, falling instead among the majority of nail biters who carry on the habit without serious side effects. Up to 45% of teenagers bite their nails, for example; teenagers may be a handful but you wouldnt argue that nearly half of them need medical intervention. I want to understand the subclinical side of thephenomenon nail biting that isnt a major problem, but still enough of an issue for me to want to be rid of it.Its mothers faultPsychotherapists have had some theories about nail biting, of course. Sigmund Freud blamed it on arrested psycho-sexual development, at the oral stage (of course). Typical to Freudian theories, oral fixation is linked to myriad causes, such as under-feeding or over-feeding, breast-feeding too long, or problematic relationship with your mother. It also has a grab-bag of resultingsymptoms: nail biting, of course, but also a sarcastic personality, smoking, alcoholism and love of oral sex. Other therapists have suggested nail-biting may be due to inward hostility it is a form of self-mutilation after all or nervous anxiety.Like most psychodynamic theories these explanations could be true, but theres no particular reason to believe they should be true. Most importantly for me, they dont have any strong suggestions on how to cure myself of the habit. Ive kind of missed the boat as far as extent of breast-feeding goes, and I bite my nails even when Im at my most relaxed, so there doesnt seem to be an easy fix there either. Needless to say, theres no evidence that treatments based on these theories have any special success.Unfortunately, after these speculations, the trail goes cold. A search of a scientific literature reveals only a handful of studies on treatment of nail-biting. One reports that any treatment which made people more aware of the habit seemed to help, but beyond that there is little evidence to report on the habit. Indeed, several of the few articles on nail-biting open by commenting on the surprising lack of literature on the topic.Creature of habitGiven this lack of prior scientific treatment, I feel free to speculate for myself. So, here is my theory on why people bite their nails, and how to treat it.Lets call it the anti-theory theory. I propose that there is no special cause of nail biting not breastfeeding, chronic anxiety or a lack of motherly love. The advantage of this move is that we dont need to find a particular connection between me, Gordon, Jackie and Britney. Rather, I suggest, nail biting is just the result of a number of factors which due to random variation combine in some people to create a bad habit.First off, there is the fact that putting your fingers in your mouth is an easy thing to do. It is one of the basic functions for feeding and grooming, and so it is controlled by some pretty fundamental brain circuitry, meaning it can quickly develop into an automatic reaction. Added to this, there is a tidying up element to nail biting keeping them short which means in the short term at least it can be pleasurable, even if the bigger picture is that you end up tearing your fingers to shreds. This reward element, combined with the ease with which the behaviour can be carried out, means that it is easy for a habit to develop; apart from touching yourself in the genitals it is hard to think of a more immediate way to give yourself a small moment of pleasure, and biting your nails has the advantage of being OK at school. Once established, the habit can become routine there are many situations in everyones daily life where you have both your hands and your mouth available to use.Understanding nail-biting as a habit has a bleak message for a cure, unfortunately, since we know how hard bad habits can be to break. Most people, at least once per day, will lose concentration on not biting their nails.Nail-biting, in my view, isnt some revealing personality characteristic, nor amaladaptiveecho of some useful evolutionary behaviour. It is the product of the shape of our bodies, how hand-to-mouth behaviour is built into (and rewarded in) our brains and the psychology of habit.And, yes, I did bite my nails while writing this column. Sometimes even a good theory doesnt help.相关内容英国前首相戈登布朗（Gordon Brown）、杰奎琳肯尼迪（Jackie Onassis）、布兰妮斯皮尔斯（Britney Spears）之间有什么共同点呢？他们都爱（或曾经都爱）咬指甲。这嗜好我可不喜欢。被别人看到多恶心呀，把双手的形象全毁了，很可能不卫生，如果咬得太深还会受伤。我也几次试图想要戒掉，但从未持之以恒。最近，我总在想是什么让像我这样爱咬指甲的人恶习难改呢？难道和其他人相比我们意志更薄弱？更神经质？更有欲望？也许心理学研究的文献能够给我答案，也许还能给我一些暗示，教我如何自我摆脱这个令人讨厌的习惯。第一次浏览文献就发现了过度咬指甲的医学术语：“咬甲癖”（onychophagia）。心理学家把它归于一种冲脉控制问题，即类似强迫症问题。但这仅指极端案例，精神病学对此的帮助颇有成效，对其他过度怪癖也是如此，如：皮肤搔抓症，拔毛癖。我可没到那种程度，只是和大多数爱咬指甲的人一样，一直有这样的癖好，但没什么严重的不良反应。45%以上的青少年爱咬指甲，比如：青少年可能只占一小部分，但你不会说他们中一半人需要接受医学治疗。我想要了解这种现象临床症状不明显的一面咬指甲没什么大惊小怪，但它对我来说依然是件大事，得去克服。都是妈妈的错当然，心理学家在咬指甲方面有许多理论。西格蒙德弗洛伊德（Sigmund Freud）把它归结于性心理发育不良，当然是在口腔期。典型的弗洛伊德理论认为，口欲滞留的原因有很多，诸如：喂食不足或喂食过盛、哺乳时间过长、或与母亲关系不睦。当然，各原因交错也导致了诸多症状的发生：当然，咬指甲是其一，还有为人尖酸刻薄、吸烟、酗酒、喜欢口交。其他理疗师建议将咬指甲归于“内在敌意”毕竟是某种形式上的自残或是紧张焦虑。像大多心理动力论这样解释也许是说的通的，但没有特别的理由说服我们去相信这些解释是对的。对我来说最重要的是：他们并没有任何强有力的说法，如何自己戒掉这个习惯。就母乳喂养的程度而言，我早已过了那时期。甚至在我最放松的情况下我也咬指甲，所以似乎也没有什么简单的解决办法。更不用说，现今没有证据证明基于这些理论上的治疗有任何特别的成效。可惜在种种猜测之后，也慢慢无从所知了。检索相关科学文献只发现一些基于如何治疗咬指甲癖的研究。其中一项研究指出：任何让人们愈发认识到咬指甲这个癖好的治疗似乎是有所帮助的，但除此之外并没有什