When people say they drank because, and then cite external circumstances, emotions, or really anything but the bare mental obsession, the bare physical craving, the twin compulsions sober and drunk, as the reason for having a drink or having another drink, they are saying not that they were powerless but that they were operating on the basis of reasoning, albeit admittedly faulty reasoning: they were in the driving seat.
The twin diagnostic features of alcoholism—the (mental) compulsion to have the first drink; the (physical) compulsion (acting through the mind) to have the next drink—are best foregrounded not by the situations that appear to explain the drinking through perception, goal-establishment, and actions designed to achieve that goal (e.g. 'I drank to escape my feelings') but by their opposite:
I had the first drink despite what I felt, believed, thought, or wanted. I had the second and subsequent drinks even though [insert list of interests, considerations, anticipated consequences].