Our obsession with cleaning could be linked to rising rates of depression, scientists claim.

科学家称，过分洁癖可能会令人更加抑郁。

They believe that eliminating bacteria and viruses has actually made our immune systems weaker, and this in turn has affected the functioning of our brains.

科学家认为，清除病毒和细菌会降低人体抵抗力，同时也会影响人体大脑功能。

Scientists have long blamed our overly sterile environments for increases in asthma and allergies. They say some bacteria are necessary for bolstering our immune systems, and without them our bodies over-react to dust and pollen, resulting in an allergy.

长期以来，科学家指责过分干净的环境是哮喘和过敏的元凶。某些细菌对增强人体免疫力至关重要。没有细菌，我们会对灰尘、花粉极度敏感，产生过敏现象。

But now researchers believe that this over-reaction may also impair the brain’s ability to produce certain chemicals that make us happy – such as serotonin – and this leads to depression.

但是，现在科学家相信过度反应可能阻碍大脑分泌某种令人高兴的化学物质，例如血清素，这样，人就变得抑郁了。

They point out that rates of depression are far higher in the Western world compared to poorer nations. Around one in ten Britons suffers from depression compared to just one in a hundred in Nigeria, for example.

另外，科学家还指出，西方国家抑郁的程度远远高于贫穷国家。抑郁在英国的比例大约是1/10;而尼日利亚的仅为1/100.