>As someone fluent in four languages*, I agree. I would even argue that the opposite of an advantage is true. Consider this: it adds unnecessary cognitive load. When trying to think of a word, it comes to you in four different languages, which isn't helpful!
I've heard that there is an unusually high rate of mental illness among European Parliament translators.
For what it's worth, I couldn't find a supporting result after a few quick searches on Google Scholar and regular Google.
At most, I found a systematic review article [1] with the conclusion that interpreters for refugees experience higher levels of emotional and work-related stress, but it seems like this is more of a result of the content being translated, versus the act of translation.
It seems plausible, too, that assuming the claim is true (though I couldn't source an article to confirm this), it may alternatively be a result of the content of the translation or the pressure of the job (e.g. there may be serious consequences if there are mistranslations), versus the act of translation itself.
I've heard that there is an unusually high rate of mental illness among European Parliament translators.