Approximately 32 to 35 million adults in the United States have an episode of major depression sometime during their lifetime, and many of them do not respond to initial treatment.[1]  This is called Treatment Resistant Depression, and can also occur in the depressive cycle for people with bipolar disorder.


The results of an analysis undertaken by Fava and Davidson  suggest that between 29% and 46% of depressed patients fail to respond fully to antidepressant treatment of adequate dose and duration, and about 15% of patients fail to respond to multiple treatment trials.[2]  


A particular problem is that anti-depressants used without a mood stabilizer tend to instigate bipolar manic episodes and/or make the bipolar disorder worse.


Treatment of bipolar depression has two particular goals:


1.    Treatment of the depression itself (stabilization)


2.    Prevention of further depressive episodes


The concept of treatment resistance is often applied to bipolar disorder when one or both of these goals are not achieved despite adequate treatment with appropriate bipolar medication.


There is dispute among professionals as to when a patient is considered to be treatment resistant to their medications.


Some doctors feel that two trials is enough to fit the definition; while others differ – to one or even three trials.   They also differ in the amount of time for a patient to be considered treatment resistant.


What it boils down to is a "trial and error" of working with different medications to see which one has the best result for the person with bipolar disorder.  Many times, this will include several medications at the same time.


Once on a medication trial, the person with bipolar disorder should respond within 1-2 weeks --- hopefully.  However, sometimes it can take even a month for full benefits of the medication to be realized.


If medication continues to be a problem for the person, their doctor may suggest Electro-Convulsive Therapy (ECT) as a way to "shock" the brain, so that medications may be tried again with a positive result.

[1] Kessler RC, Berglund P, Demler O, et al. The epidemiology of major depressive disorder. results from the National Comorbidity Survey replication (NCS-R). JAMA. 2003:289:3095-3105.

[2] Fava M, Davidson KG. Definition and epidemiology of treatment-resistant depression. Psychiatr Clin North Am. 1996;19:179-200.