niepoczytalność po angielsku:

it would be insanity to expand the business at the moment

The insanity of the situation made him laugh.

Genius is only one remove from insanity.

I don't suffer from insanity - I enjoy it!

But he who knows what insanity is, is sane; whereas insanity can no more be sensible of its own existence, than blindness can see itself.

I doubt if a single individual could be found from the whole of mankind free from some form of insanity. The only difference is one of degree.