Unfortunately when the account is closed several things are happening. First, it is no longer helping your mix of credit if closed. A lack of a CC credit mix can really tank your scores. Also, if you have balances on a closed account then you put yourself in a position to be charged-off or sent to collections, even if you are making payments, which is of no help to your scores obviously. Ideally, you'd want to keep them open. Finally, closing cards will not hurt your history, now, however the 10 yr clock starts and when they are removed 10 yrs from now off your CR, your AAoA will tank as will your future score.
They can usually be reopened.
Impulse buying is an addiction. I'm coming clean here and am admitting that DW and I racked up over $20,000 in CC debt this past year to year and a half. It wasn't all at once and we didn't buy stuff we didn't need but we slowly overextended our budget and went out to eat more, bought more clothes for us and the kids, went to the movies, over extended our Christmas shopping on '07, etc. Moreover, I took a two month temp. pay cut and supplemented with our CCs. We realized in this past August that things were getting way out of hand and paid down over 25% of it already, but isn't fast enough. However we are about to pay off a car and that will free up over $600 per month.
We made the decision to stop using our CCs. We never cut them up, but we did shelve them. I don't carry CCs at all and leave them at home. DW does the same. All we have is a debit card and if there's no money in the bank then I don't buy anything. Mentally, I associate pain with spending. Watching our FICO scores plummet was an instant cure for me too.
You have to do what is best for you. My wife has a Psych degree, but she uses that to figure me out. Wish I could offer more advice. One thing I'll say is do whatever it takes to prevent future damage. That may include cancelling all of your cards if things can get out of hand. You can get a 600+ FICO score without the use of CCs.