Unexpected uncertainty can breed paranoia

出乎意料的不确定性会导致妄想症

上海译锐翻译    2020-6-11   16:01

In times of unexpected uncertainty, such as the sudden appearance of a global pandemic, people may be more prone to paranoia, Yale University researchers suggest in a new study published in the journal eLife.

当出现突如其来的突发事件时，比如全球瘟疫突然爆发，人们可能更加容易产生妄想症，耶鲁大学研究员在发表于期刊eLife中的一篇论文中提出以上观点。

"When our world changes unexpectedly, we want to blame that volatility on somebody, to make sense of it, and perhaps neutralize it,'' said Yale's Philip Corlett, associate professor of psychiatry and senior author of the study. "Historically in times of upheaval, such as the great fire of ancient Rome in 64 C.E. or the 9/11 terrorist attacks, paranoia and conspiratorial thinking increased."

“当我们的世界发生一些意想不到的变化时，我们希望将这一剧变怪罪在某个人头上，想把这些变化弄清楚，或也许希望能够淡化它”，耶鲁大学精神病学助教兼研究资深作者Philip Corlett表示。“历史上所出现的动荡剧变，比如公元后64年古罗马的大火或9/11恐怖袭击，都会造成妄想症和阴谋思维增加。”

Paranoia is a key symptom of serious mental illness, marked by the belief that other people have malicious intentions. But it also manifests in varying degrees in the general population. For instance, one previous survey found that 20% of the population believed people were against them at some time during the past year; 8% believed that others were actively out to harm them.

妄想症是严重精神障碍的一个主要症状，其特征是认为其他人怀有恶意。但是妄想症在普通人身上也有所体现，只是程度不一。比如，在之前所做的一项问卷调查中，我们发现，有20%的人认为在过去的某段时间内，有人总是针对自己；有8%的人认为别人一心想要伤害自己。

The prevailing theory is that paranoia stems from an inability to accurately assess social threats. But Corlett and lead author Erin Reed of Yale hypothesized that paranoia is instead rooted in a more basic learning mechanism that is triggered by uncertainty, even in the absence of social threat.

比较普遍的一个理论是妄想症起源于无法正确评估社会威胁。但是，耶鲁大学的Corlett和首席作者Erin Reed则假设，妄想症其实根源于某个更加基础性的认知机制，这一认知机制由不确定性所触发，即使是在没有社会威胁的情况下。

"We think of the brain as a prediction machine; unexpected change, whether social or not, may constitute a type of threat -- it limits the brain's ability to make predictions," Reed said. "Paranoia may be a response to uncertainty in general, and social interactions can be particularly complex and difficult to predict."

“我们将大脑看做是一个预测机器；意料之外的变化，无论是社会性的还是其他类型的，都可能造成一种威胁-它会对大脑预测的能力做出限制”，妄想症可能是对普遍不确定性的反应，而社会交往则特别复杂且难以预测”。

In a series of experiments, they asked subjects with different degrees of paranoia to play a card game in which the best choices for success were changed secretly. People with little or no paranoia were slow to assume that the best choice had changed. However, those with paranoia expected even more volatility in the game. They changed their choices capriciously -- even after a win. The researchers then increased the levels of uncertainty by changing the chances of winning halfway through the game without telling the participants. This sudden change made even the low-paranoia participants behave like those with paranoia, learning less from the consequences of their choices.

在一系列实验中，他们请具有不同程度妄想症的受试对象玩一种纸牌游戏。在这个游戏中，获胜的最佳选择被秘密改变了。几乎或完全没有妄想症的受试对象会在较长时间之后才会设想最佳选择已经发生变化。但是，有妄想症的人群则会预计游戏会存在反复无常。他们会突然改变自己的选择-甚至是在赢牌后。研究人员随后通过在游戏进行到一半时改变赢牌的几率来增加游戏的不确定性。这一突如其来的变化使那些即使是妄想症程度较低的人群也表现的和有妄想症的人群一样，并未从自己选择的结果中获得经验。

In a related experiment, Yale collaborators Jane Taylor and Stephanie Groman trained rats, a relatively asocial species, to complete a similar task where best choices of success changed. Rats who were administered methamphetamine -- known to induce paranoia in humans -- behaved just like paranoid humans. They, too, anticipated high volatility and relied more on their expectations than learning from the task.

在一个相关的实验中，耶鲁大学合作伙伴Jane Taylor和Stephanie Groman对老鼠，一个相对不合群的物种进行了训练。在实验中，老鼠需要完成类似的任务，但是在要完成的任务中，最佳的选择发生了变化。被注射甲基苯丙胺（一种可以导致人类出现妄想症的成分）的老鼠的表现和有妄想症的人群完全一样。它们同样倾向于认为事物反复无常并且更多的依赖于自己的期待而非从任务中学到的经验。

Reed, Corlett and their team then used a mathematical model to compare choices made by rats and humans while performing these similar tasks. The results from the rats that received methamphetamine resembled those of humans with paranoia, researchers found.

Reed、Corlett及其团队在进行上述类似的任务时，使用数学模型对老鼠和人类所作出的选择进行对比。被注射甲基苯丙胺的老鼠试验结果和妄想症人群的实验结果非常相似。

"Our hope is that this work will facilitate a mechanistic explanation of paranoia, a first step in the development of new treatments that target those underlying mechanisms," Corlett said.

Corlett认为，“我们希望这一研究从机理的角度进一步解释妄想症，这也是推出新治疗方法的第一步。新的治疗方法以妄想症存在的潜在机理为目标。”

"The benefit of seeing paranoia through a non-social lens is that we can study these mechanisms in simpler systems, without needing to recapitulate the richness of human social interaction," Reed said.

Reed表示，从非社会性单价角度去看待妄想症有一个好处，那就是我们能够在更简单的体系内研究这些机理且无需重述人类社交互动的丰富性。

文章来源：科学日报    编辑：质控部