18:50 Jul 10, 2009 

I agree with both, the points raised and the alternatives you have suggested.

Personally I think in actual translation one would translate it as used in normal parlance in the target language unless specifically asked to provide a literal translation. In this particular case, I think giving a literal translation is also valid because this site I understand is open to both, for use in translation or just to know or understand a term/phrase and the individual words that make up the phrase/sentence, and /or be able to use it to say to someone or understand what someone may have said to you.

The usage is also age related perhaps! Qislam gave the direct translation in words most spoken by young people - 'are you mad? 'are you crazy? and following from that I have thought of "have you gone mad / crazy?" Perhaps I am too old to have thought of them straightaway!!

There are of course lots of slang words /phrases in English, as in all languages.

18:12 Jul 10, 2009 

With a phrase like this a choice needs to be made between (a) a translation which is faithful to the original and (b) an idiomatic phrase in the target language. Also, with such an idiomatic phrase you need to take account of your readership: for instance, what works in Indian English may not be recognised in other variants.

nke and qislam have made very valid suggestions for turning the phrase round, to achieve the same communicative effect. In a similar way, you could combine elements of all the answers with a phrase such as "Have you taken leave of your senses?". This is idiomatic and fairly common in British (and I think also American) usage.

If you wanted to stay closer to the original, you could use a phrase such as "Are you in your right mind?". This is also idiomatic and fairly common in British (and I think also American) usage.

However "to be in one's senses" is not in common British or American use.