"OCD, I'd like you to meet my friend, D-cycloserine. D-cycloserine, this is OCD. I think you two should get to know each other a little better. You just might have a future together..."

As someone who has long been enamored with basic science, I find it fascinating when classic medications are re-purposed in surprising ways.  One of the newest examples of this is the use of D-cycloserine (also known as Seromycin) in the treatment of obsessive-compulsive disorder (OCD).

What’s interesting about D-cycloserine is not so much what it is…but what it isn’t:

• D-cycloserine is neither an SRRI nor any other type of antidepressant (e.g., Prozac).
• It’s not an anti-anxiety medication (e.g., Xanax, Klonopin).
• It’s not even an atypical antipsychotic (e.g., Abilify, Risperdal).

If it’s not one of the above, then what is it?

The answer might surprise you.  Seromycin is actually an antibiotic that was originally developed to help fight off tuberculosis.  What’s exciting about using an antibiotic to treat OCD is that it’s not subject to the same side effects as other medications (i.e., the SSRIs, anxiolytics, or antipsychotics).  In fact, most clinical studies have found few, if any, significant side effects when using D-cycloserine in OCD treatment.

Before I go further, there’s an important caveat to keep in mind:

Research on D-cycloserine in OCD treatment is still a work-in-progress, so it’s important to maintain some healthy skepticism on this issue.

Research studies looking at using D-cycloserine to treat OCD have been fairly limited, and the results of these studies have been mixed.  Some studies have suggested that the medication has small or non-significant effects, whereas other studies have found the medication to be beneficial.  Several recent, placebo-controlled studies have been quite promising and have indicated that taking seromycin can initially “speed up” the therapeutic response to exposure and response prevention therapy (ERP), a form of cognitive behavioral therapy (CBT) developed to treat OCD.  In essence, you benefit more from initial ERP therapy sessions.  D-cycloserine doesn’t appear to have any effects on OCD when taken on its own (i.e., when not combined with exposure and response prevention).  For more information regarding how ERP is thought to work, visit my blog post here.

It’s important to note that D-cycloserine doesn’t appear to offer any long-term benefits above and beyond what you would get from ERP alone.  In the end, you’re likely to achieve the same amount of symptomatic improvement whether or not you take the medication.  However, the research indicates that you’re likely to get more “bang for your buck” if you’re taking Seromycin during early exposure sessions.  This is important, because it reduces early treatment frustration and drop out.

How does D-cycloserine work?  Does the fact that it is an antibiotic mean that OCD is caused by bacteria?

No.  Like most medications, D-cycloserine is a complicated chemical that has many different biological effects.  It is not D-cycloserine’s antibiotic properties that are thought to make it useful in OCD treatment, but rather how this medication works on certain neurotransmitter receptors in the amygdala (a part of your brain that is associated with emotions like fear).  Without getting too technical, D-cycloserine is thought to affect certain amygdala receptors (i.e., NMDA receptors) that are associated with learning and memory.  Researchers theorize that action at these receptors facilitates learning/fear extinction, which is why the medication can apparently augment learning-based treatments like ERP.  On a related note, feel free to read my short blog post on whether or not ERP works via learning or unlearning here.

Can D-cycloserine be used to treat other anxiety disorders? 

Yes.  Research indicates that behavioral treatment of other anxiety disorders (panic, phobias, and the like) may also be enhanced by the addition of D-cycloserine.  Again, overall symptom reduction may be the same whether or not the medication is used; however, the addition of seromycin may help individuals benefit more from early exposure sessions.

Final note: As a psychologist, I cannot prescribe medications; however, you’re welcome to visit my practice in Palm Beach County, Florida for exposure and response prevention (OCD) therapy. I see individuals from Palm Beach Gardens, Jupiter, and West Palm Beach, as well as the surrounding communities (including Fort Lauderdale & Miami). For more details about D-cycloserine and other medications for OCD treatment, consult with your medical doctor or psychiatrist.

You can also access some of the original research about D-cycloserine at the links below:

Some Effects Found:

• D-Cycloserine Augmented Exposure Therapy for Obsessive-Compulsive Disorder (abstract only)
• A Meta-Analysis of D-Cycloserine and the Facilitation of Fear Extinction and Exposure Therapy (full-text)
• Augmentation of Behavior Therapy With D-Cycloserine for Obsessive-Compulsive Disorder (full-text)

No Effects Found:

• D-cycloserine does not enhance exposure-response prevention therapy in obsessive-compulsive disorder (abstract only)

Questions? Comments? Sound off below.

…or continue the discussion on Facebook, Twitter, or Google+.