what condition/name is given when someone goes on an impulse, knows it's wrong but can't stop themselves and has been diagnosed with clinical depression

example:

a teenager who knows it's wrong to purchase items off the internet even after all cards are hidden and/or pin numbers changed still finds a way to do it and doesn't stop until they are caught (bills come in) then hang their head and quietly say.....sorry I don't know what got into me

please someone must know what it is and where or how I can find help for this teenager