Are you powerless? What a question! Nobody wants to think of themselves as being incapable or inept. The word "victim" leaves a tang in your mouth that smacks of weakness. Yuck. That being said, how else would you describe the phenomenon of addiction?
Abusing alcohol and other drugs actually alters brain chemistry. In effect, the abuser takes over the responsibility of commanding the body when to feel joy. Now they feel pleasure on demand. What a thing! However, just like eating Hershey's Kisses, one is never enough. Feeling that good is so good, it reinforces the need to experience it again and again.
Tolerance builds and builds as the body adapts to the intake of poison. Tolerance results from brain cells becoming desensitized to, and depleted of, dopamine. So the abuser experiences less and less bliss even though they are using more and more poison. Nevertheless, they are compelled to continue even when there is no more enjoyment to be had. They have mismanaged the body's reward process by draining the brain of natural feel-good chemicals like dopamine.
The greater the brain-drain, the more anxious and depressed the abuser feels whenever they are not high or drunk. Compulsive substance use is now producing the opposite effect than intended. You can see this effect at work in alcoholics who need a drink to stop shaking in the morning. You see it in the opiate dependent person who swallows many times the recommended dosage and - instead of being knocked out - becomes clear-headed and energetic. And you see it in the heroin user who must shoot up every few hours like clockwork in order to feel comfortable in their own skin. In each case, the substance has the opposite effect. Brain scans show that brain drain affects the abuser long after they quit.
So why would someone continue paying for, and using, something that drained their head of good chemicals (and all common sense)? It's not by choice! Substance abuse is a brain disease of which drugs and alcohol are symptoms. Admitting you are powerless is not the end. It is the beginning.