Why do antidepressants stop working?

In reading your comments, I'm struck by a number of observations:

Many of you have suffered for a long time with depression but haven't given up. Most impressively, many are trying to help others.It's common to find an antidepressant medication that works for awhile and then after some months or years, it stops working. This is extremely frustrating for you and your doctor. The truth is that we don't really understand why this happens. There are probably different reasons for different medications. Fortunately for some of you, it doesn't happen.National Suicide Prevention Lifeline
1-800-273-TALK (8255) Go to the nearest hospital or emergency roomCall your physician, health provider or clergyNational Alliance on Mental Illness
www.nami.org
1-800-950-NAMI (6264)

When you're doing well on an antidepressant, it's reasonable to ask how long you should keep taking it. Unfortunately, there's no absolutely correct answer. However, most clinicians feel that as long as the medication is having a beneficial effect, it's probably wise to keep using it. This is particularly true because some of you do well on the same medication for many years.

One of the current theories for why antidepressants stop working is that over time the genes that produce enzymes that regulate the metabolism of medications become upregulated and consequently produce more enzymes. If this is the case, it may lead to a decrease in the blood level and it may be necessary to increase the dose in order to get the same effect.

Some of you decide to stop taking antidepressants when you feel better, and then find that symptoms return. At that point, you want to begin taking the medication again. For some, the medicine once again helps, but for others it doesn't seem to have the same positive effect that it initially had.

It would be helpful if you'd share your own stories related to a particular medication losing effectiveness. The personal stories might provide some clues that could help others to better understand why a particular antidepressant medication stops working. It would be important to know the name of the medication that initially worked and what events were associated with it losing its effectiveness. While it's frustrating to have a medication lose its effectiveness, usually a replacement can be found that will once again lead to some relief of depressive symptoms.

One of you asked about being an ultrarapid metabolizer. This means that for some antidepressants it would be difficult for you to achieve an adequate blood level and therefore it would be unlikely you'd have a good clinical response at a safe dose.  However, it's important to understand that even though someone is an ultrarapid metabolizer for one type of antidepressant, it's quite possible that they could be a normal metabolizer of other antidepressants. This is a critical concept for both patients and their doctors to understand.Another question was how pharmacogenomic testing can be obtained in Canada.  It's my understanding that it's available at the major academic medical centers in Canada as they have good access to major reference laboratories which all offer pharmacogenomic testing. However, I don't believe that it's routinely paid for by the Canada's national health system. Hopefully, this will change as the benefits of testing become more widely understood.blog index