But as the weeks in quarantine pile up, what started out as a way to unwind may, for some, start to feel like an unexpectedly stubborn habit. And for those who are in recovery, the combination of stress and social distancing can make maintaining sobriety all the more challenging.

Alcohol and drugs light up the neurotransmitters associated with pleasure. They also offer relief from the unpleasant symptoms associated with stress, decreasing fear and anxiety, relaxing muscles, and slowing speeding heart rates, said R. Kathryn McHugh, an assistant professor of psychology at Harvard Medical School and the director of the Stress, Anxiety and Substance Use Laboratory at McLean Hospital in Belmont, Mass.

“The tricky part is, the higher your stress is, the more that relief is reinforced,” Dr. McHugh said. “When we get that huge relief, that makes us more likely to continue to go back to that substance.”