What condition results from a long-term deficiency of vitamin B-1?

The condition that results from a long-term deficiency of vitamin B-1, or thiamine, is beriberi. This disease can manifest in several forms, including wet beriberi, which affects the cardiovascular system, and dry beriberi, which primarily affects the nervous system. When thiamine levels are insufficient, the body cannot metabolize carbohydrates effectively, leading to symptoms such as muscle weakness, nerve damage, and heart complications.

Korsakoff's psychosis, alcoholic dementia, and Wernicke's disease are often associated with chronic alcohol use and thiamine deficiency, particularly in individuals with long-term alcohol dependence. While these conditions share a relationship with thiamine deficiency, they specifically relate to more severe neurological impacts versus the broader classification of beriberi.

Since beriberi represents a direct consequence of vitamin B-1 deficiency, it accurately captures the essence of the question regarding the result of prolonged lack of this essential nutrient.