Until 2013, I had major problems with money. Even after my bankruptcy in 2005, I was able to get a credit card. My whole adult life I was overdrawn at the bank and my credit cards were maxed out. Shopping sprees galore. (I wasn't diagnosed until I was 59).
I was on Abilify in May, and it made me hypomanic. Online shopping became a problem, but I was restricted due to having no credit of any kind, thank heavens. I sold my bicycle to pay for the online shopping I had done. I stopped Abilify and the hypomania went away.
Since 2013, when I went on disability, I have had no credit cards or loans, and I've had a very low fixed income. I have a prepaid Mastercard only. I finally learned to budget, and sometimes I have money left over at the end of the month. Its never a lot of money, but any savings at all is a kind of victory for me. Having no credit is a blessing for me.