It is one of the most common and wrenching decisions in mental health: when to stop antidepressant medication.

The big risk of going off the drugs is the possibility of relapse. Those who have had one episode of depression have a 50 percent chance of having a second. Those who have had two episodes have an 80 percent chance of having another. Continuing on antidepressant medication can cut the risk of relapse in half, according to a review of 15 clinical trials that was published in the Journal of Clinical Psychiatry in 2014.

But antidepressant medications can come with significant side effects, including weight gain and sexual dysfunction. Some patients complain of flattened emotions. While the most popular drugs, selective serotonin reuptake inhibitors or SSRIs, appear to be very safe, even long-term studies tend to follow people for only a few years. With many people first diagnosed with depression and anxiety disorders in their 20s and 30s, the prospect of taking medication for decades may not be appealing—especially among those who have been feeling well for years.

Now, researchers are looking for patterns of brain activity or other indicators that might reveal which people are most likely to relapse. Those most at risk might be advised to stay on antidepressants long-term. Scientists are also studying whether certain psychological treatments can prevent relapse after patients go off medication.

Click for more from The Wall Street Journal.

More on this...