Most relapse is not relapse. It is a resumption of untreated alcoholism after a tiny little break. The main cause of such 'relapse' is ... not recovering from alcoholism in the first place.
To recover from alcoholism, take the first nine Steps punctiliously, retake them regularly, and live concertedly in Steps Ten through Twelve.
Relapse can occur only when someone has recovered. It's much rarer, in part because so few actually recover.
Here are some of the risk factors, as reported to me by people who have relapsed and as sensed by me in observation of my own proximity to potential relapse:
- Abandoning or slacking off with Steps Ten through Twelve
- Failing to redo the first nine Steps on a regular basis
- Prescription-/pharmacy-hunting for mind- or mood-altering substances
- Carelessness with legitimate prescription or over-the-counter medication
- Carelessness with products containing alcohol
- Allowing other addictions to become activated or flourish
- Becoming disgruntled with AA and leaving because people are stupid, boring, repetitive, sick, manipulative, getting it wrong, or whatever else is apparently irksome
- Abandoning AA entirely to pursue another spiritual or religious path instead
- Going deep into a Higher Power-free spiritual path which, by design or inadvertently, leads to darkness, negative philosophies, self-obsession, or self-enthronement
- Assuming 'expert status' in AA because of outside status as a therapist, recovery industry professional, etc.
- Materialism, individualism, hedonism, sensualism.
Other than that, one is usually on safe ground.