I am a compulsive liar when I drink. I never used to be, but that was before I lost my career, my car, my apartment, and girlfriend. I lie as a defense mechanism to hide the true extent of alcoholism and how far I have fallen. Show me an alcoholic and I'll show you a liar. It comes down to great shame I feel about being a drunk. Although, hearing people speak in AA has been helping me get over the shame. I am making progress as far as forgiving myself. Either that or I just don't care about it anymore.