If a person "chooses" to drink at deliberate odds with the facts of his circumstances and his established history, one has to question his sanity.
An insane person, e.g. someone who believes that, when he jumps off a roof, he can fly, indeed believes in his own power of choice in the moment of decision.
A dispassionate, third-party appraisal of the situation, however, would reveal that a major distortion of reality has fatally impaired the individual's decision-making faculty.
Whether the individual, in the moment the decision is made, perceives himself to be choosing freely is irrelevant.
The truth is that there is a drive within him ("I want to drink") plus a distortion of reality (the "peculiar mental twist") that makes fulfilment of the drive possible.
It can be rightly said that the drive is prompting the decision, the mental twist is enabling it, and there is no GENUINE choice in the sense of the selection of the best option on the basis of a rational appraisal of the facts.
True "choice" is predicated on the application of reason. Without reason, there is no genuine choice; one is at the mercy of drives whose genesis one cannot control.