Why Do Antidepressants Need Several Weeks to Become Effective?

Reader’s Question

I have a few questions. I have been taking an antidepressant for depression and anxiety. I was taking Celexa, but found that it just wasn’t doing the trick so my doctor switched me to Prozac. It’s been a little over 2 weeks on it and I do feel better. I am not consumed with worry and fear and am able to go about my day, but as for feeling like myself and having a happy mood I don’t have that. My doctor told me that a lot of times the medicine will deal with anxiety first and then begin to kick in for depression. Is that true? Is it also still expected that the Prozac still needs 4-5 weeks to reach it’s maximum level? Thanks so much!

Our Consulting Clinical Psychologist’s Reply

When we are dealing with depression, it’s helpful to imagine traveling from mild symptoms (poor concentration, tension), to moderate symptoms (impaired sleep/appetite/sex drive, social withdrawal, sadness, fatigue), and finally experiencing severe symptoms (explosive outbursts, uncontrollable crying spells, increased mind speed, inability to function, suicide ideation). Depression is thought to be the result of decreased levels of a neurotransmitter called Serotonin. I often use an automobile engine as an example of being one, two or three quarts low on oil. Three quarts low of Serotonin and like your automobile engine, things start to seize up and stop working — you can’t go to work, cry constantly, etc.

Prozac, like most antidepressants, works by slowly increasing the availability of Serotonin in the brain. Prozac is in a class of medications called SSRI’s — Selective Serotonin Reuptake Inhibitors. When we start treatment with an antidepressant, usually when the individual is very low in Serotonin and experiencing severe symtoms, it takes 4 to 6 weeks to fill up the crankcase…or brain. The slow accumulation and return of Serotonin causes the worst symptoms to come under control first — like we are backing out of the depression. As you noticed, the worry and fear that was incapacitating you has gone, but it was one of the most severe and recent symptoms to arrive. As you back out of your depression, sleep and appetite should stabilize, humor should return, and the “old you” should pop out in about 6 weeks. This is why your physician described how the anxiety is stabilized first — as it’s more socially disabling than the depression. Sad people can often work but those with panic attacks can’t — that kind of thing.

So far, you’re right on schedule. 35% of folks on antidepressants try at least two before finding the medication right for them. For additional information I’d read two articles I’ve written entitled Chemical Imbalance and Understanding Depression — both available on my website at www.drjoecarver.com. You and your physician are on the right track. Backing out of a depression is a slow process, but it probably took six to nine months to get in that hole. Also remember that once the old you has returned, it’s a good idea to continue the Prozac for an additional 6 to 9 months to allow time to repair the damage to your self-esteem and self-confidence that occurs during a depression.

You’ll be laughing again soon.