Brain chemistry, aside- the book of Alcoholics Anonymous was written by people, that have done more for the “benders”, than anyone in oral or written history. Apparently, a spiritual recovery is foremost- in realigning a healthy physical/mental condition.
A spiritual recovery is great, but if you have an organic imbalance in your neurochemistry, psychological and physical stuff can happen that is very dramatic. Making it worse is that it is very interactive with your hormones and immune system.
The problem was less the bender itself than the chaos it caused in their brain chemistry.
As an analogy, a painter has been carefully painting a detailed picture for some months, then he gets drunk and makes the painting all sloppy. When he sobers up, he may decide not to get drunk again and spiritually recover, but his painting is still fouled up and will take a long time, if ever, to fix.
His AA friends can help him with his spiritual recovery, but there is not much they can do about his painting, no matter how experienced they are.