Such people experience problems with memory, fast and efficient thinking abilities and solving problems. Though, these signs may show up in people who are aging, it may appear early in heavy smokers and drinkers.
"Several factors — nutrition, exercise, comorbid medical conditions such as hypertension and diabetes, psychiatric conditions such as depressive disorders and post-traumatic stress disorder, and genetic predispositions — may also influence cognitive functioning during early abstinence," said Timothy C. Durazzo, co-author and assistant professor in the department of radiology and biomedical imaging at the University of California San Francisco.
"In general, people show cognitive decline in older age. However, it seems that years of combined alcohol and cigarette use exacerbate this process, contributing to an even greater decline in thinking skills in later years," researchers concluded.