The first appearance of this quote was from the 1981 Narcotics Anonymous Basic Text approval form. Here is the quote in context:
"We have a disease: progressive, incurable and fatal. One way or another we went out and bought our destruction on the time plan! All of us, from the junkie snatching purses to the sweet little old lady hitting two or three doctors for legal prescriptions, have one thing in common: we seek our destruction a bag at a time, a few pills at a time, or a bottle at a time until we die. This is at least part of the insanity of addiction. The price may seem higher for the addict who prostitutes for a fix than it is for the addict who merely lies to a doctor, but ultimately both pay with their lives. Insanity is repeating the same mistakes and expecting different results."
Curiously, this quote has also been misattributed to Benjamin Franklin and Confucius. I 'm actually quite happy that Einstein didn't say it because in quantum mechanics, you actually DO expect different results in certain instances. You can see what Einstein thought of quantum mechanics here.