Heavy drinkers can partly recover from alcohol-related brain damage with sustained abstinence, but new research shows that this process can be slowed if patients continue to smoke cigarettes, Science Daily reported May 11.

MRI studies show that individuals who quit drinking but continue smoking experienced less improvements in blood flow in brain regions like the frontal and parietal cortices, which are often damaged by heavy drinking.

The brain’s frontal lobes are involved in learning, short-term memory, reasoning, planning, problem solving, and emotional control, while the parietal lobes are involved in attentional regulation and visuospatial processing, according to researcher Anderson Mon of the University of California at San Francisco.

“At one week of abstinence, both smoking and nonsmoking … patients had similar frontal and parietal gray-matter perfusion [blood flow]; and both groups had lower perfusion than normal controls,” said Mon. “However, after five weeks of abstinence, frontal and parietal gray matter perfusion of the nonsmoking … patients recovered to normal control levels, whereas the smoking … group essentially showed no recovery.”

The research suggests that patients who can handle quitting both alcohol and smoking simultaneously should be encouraged to do so in order to speed up their cognitive recovery.

The study was published online in the journal Alcoholism: Clinical and Experimental Research.