Symptoms of thiamine deficiency, or a lack of vitamin B1, include fatigue, irritability, depression and stomach problems.Thiamine deficiency is not common. However, people with Crohn's disease or anorexia, those undergoing kidney dialysis and people with alcoholism are at risk of having low thiamine levels.hiamin deficiency in alcoholics leads to a disease called Wernicke-Korsakoff syndrome/encephalopathy, which leads to many symptoms and signs which mimick drunkenness. These include double vision, staggering, poor muscle coordination, and mental confusion. Thiamin deficiency can be prevented by eating good food sources.