I'm going through a three stages medical checks before getting hired as a non armed security guard at an airport. At the next appointment I have to bring an anamnesis certificate, filled in by my doctor, in which you have to state if you have or had mental health issues. Obviously mine states bipolar disorder. 

Can the company refuse to hire me because of this?

The certificate is for the then eventual release of a firearms licence, though the job doesn't involve using one.

I'm not in the US but in Europe. 

Thanks to everyone who will answer.