When talking about gaps in memory I'm not necessarily talking about days,weeks or months but specific events,dates,numbers that just a minute or two of focus would have revealed. Or simple things like a person sober enough to realize someone is doing chores,cleaning,fixing etc. Or all the details or processes needed to get a job done at work.
Many of the alcoholics and/or abusers Ive known hate detail, they want things simplified. And maybe the abuse is sign of something else like somekind of attention deficit disorder or something. But how can persn focused on their substance gravings,their buzz or hang over be focused on many the details they come across in daily life.
Yeh I find it hard to believe that people can forget or have no memory of prolonged periods of time but I think they miss out on many of the little pieces of the puzzle that make up life and/or events.