Yes, it is normal for them to ask what the money was spent on - you might have a gambling habit (not saying you have!) They will need to know about all of your debts including credit cards etc.
Sharing from experiences of dealing with debt
The greatness of a man is not in how much wealth he acquires, but in his integrity and his ability to affect those around him positively.
Bob Marley. http://kallis3.blogs.iva.co.uk