Individuals differ in their sensitivity to alcohol's physiological effects, including blacking and passing out. Blackouts are periods of impaired memory formation when an individual engages in activities they later cannot recall, while passing out results in loss of consciousness.. To read the full article, log in using your NHS Athens details. To access full-text: click “Log in/Register” (top right hand side). Click ‘Institutional Login’ then select 'OpenAthens Federation', then ‘NHS England’. Enter your Athens details to view the article.