The Social Security Administration will first determine if you are disabled with all of your conditions including addiction. If Social Security decides you are disabled they will then decide if the addiction was not present would you still be disabled. Social Security will may find you disabled but deny your claim if it is felt drugs and alcohol are contributing to your symptoms causing marked limitations.
A doctor’s statement indicating you would be disabled even if there was no drug or alcohol addiction may help Social Security reach a decision in your favor. The doctor’s statement would need to include details of why your symptoms would remain severe if drugs and alcohol were not being used. In my experience if you are in treatment and not using for a long period of time and still having marked limitations from your illness Social Security will find you disabled.