Answer and Explanation:
1. Because alcohol stimulates behaviors and thoughts that we cannot control, but that are part of our personality. The use of alcohol allows Poe's people to unleash the worst of themselves, be it deep sadness, or an influential and delusional paranoia.
2. Because alcohol modifies the cognitive capacity of human beings, leaving them completely without any inhibition. Poe's character had evil within him, which was inhibited during moments of sobriety, but which loosened and became actions with the influence of alcohol.
3. Because Poe knew very well the effects of alcohol and the reasons that stimulated drinking, as well as the feeling that invaded a person after the effect of alcohol passed, that way he was able to write realistic characters, inspired by himself.