DEAR DOCTOR K: I’ve been on an antidepressant for about a year, and I’m feeling much better. Why can’t I just discontinue it?

DEAR READER: There’s actually a very good reason: If not handled carefully, coming off your medication can cause disturbing symptoms – and it can set you up for a relapse of depression.

Of course, you have the right to do anything you want with your medications. But I think you should talk with your doctor first about whether to stop the medication, and how. If you decide to stop, your doctor probably will advise you to taper the dose slowly. By doing so, you can minimize or avoid the symptoms that can occur if antidepressants are stopped too quickly.

Why do so-called “discontinuation symptoms” occur in the first place? Antidepressants work by altering levels of neurotransmitters. These are the chemical messengers that are sent by one brain cell (called a neuron) and then attach to another brain cell and affect its function. Neurons get used to a certain level of neurotransmitters. If you suddenly stop taking your antidepressant, neurotransmitter levels will drop quickly. This can cause a constellation of symptoms. They’re not dangerous, but they may be uncomfortable.

How long should it take to taper off your medicine? I wish I had an answer based on a scientific study. There are only a few studies, and my assessment of them is that it’s best to taper the dose by about 25 percent each week, over three to four weeks.

Even though you are the best judge of whether your depression and anxiety are returning, check in regularly with your doctor after you’ve stopped the medication.