Which mental illnesses can long-term alcohol abuse cause or increase the risk of?

Memory problems. Long term alcohol abuse can cause something called amnestic syndrome as part of a condition called wernicke-korsokoff syndrome. With such a condition, a person's short term memory is greatly diminished and in severe cases, non-existent. One can imagine the problems not being able to remember any new information can cause. An individual with such a problem can forget all new information.