Antidepressants, despite the name, are first-line treatments for anxiety as well as depression.

Choosing the right antidepressant is hard, a topic we’ll come back to frequently. It involves a lot of trial and error, but there is both some science to it and some knowledge to be drawn from practical experiences.

Here are two pieces of practical experience that don’t seem to be as well known as they should be:

  1. Wellbutrin tends to increase anxiety in a lot of people.
  2. Higher doses of SNRI’s (e.g. Effexor, Pristiq, and Cymbalta) tend to increase anxiety in a lot of people.

Usage of Wellbutrin

Wellbutrin, generic name bupropion, can be used by itself to treat depression. It’s also used as a smoking cessation aid, marketed under the name Zyban. But more often, it’s added to another antidepressant to either complement it, or reduce the impact of the first antidepressant’s side effects.

For people who get “slowed down” a bit when taking an antidepressant, sometimes Wellbutrin can help give them a little bit more pep. It’s also very commonly used to combat the dreaded sexual side effects brought on by many antidepressants.

Using Higher Doses of SNRI’s

SNRI’s like Effexor (venlafaxine), Pristiq (desvenlafaxine), and Cymbalta (duloxetine) are commonly prescribed antidepressants that can help with a wide range of anxiety and depressive symptoms.

Everyone is different, but most people start at a low dose of each and may gradually increase. Most people top out around 225mg of Effexor, 100mg of Pristiq, or 60mg of Cymbalta. But you can certainly go quite a bit higher on all of them. After all, if you’ve gotten a good response at a particular dose, maybe you’ll get a better response at an even higher dose?

Taking a Step Back

Before going any further, let’s take a step back and get a refresher on what antidepressants actually do. Your brain has a set of chemicals called neurotransmitters which help control your mood. There are several different neurotransmitters, most notably serotonin, norepinephrine and dopamine, which all affect slightly different aspects of your mood.

Different antidepressants target different neurotransmitters. They don’t actually create more of them, but they make sure that they’re all available right where they are needed. Selective Serotonin Reuptake Inhibitors (SSRI’s) work to maximize the availability of serotonin. Serotonin-Norepinephrine Reuptake Inhibitors (SNRI’s) work to maximize both serotonin and norepinephrine availability. And so on.

Neurotransmitters and Anxiety

For most people, increasing the amount of serotonin available will help improve anxiety symptoms. That is why SSRI’s and SNRI’s tend to be the first meds prescribed for anxiety.

What isn’t most recommended to try first for people with anxiety? Antidepressants that increase the amount of dopamine that is available, which makes many people more anxious, not less.

Guess what neurotransmitter Wellbutrin tends to target? Dopamine.

So what about SNRI’s? The current generation do, as the name suggests, primarily target serotonin and norepinephrine. But they also weakly target dopamine as well. However the larger increase in serotonin tends to more than offset the small increase in dopamine availability for most people.

As you move to higher and higher doses, the amount of extra serotonin made available gets smaller and smaller. That is why increasing the dose of some drugs past a certain point doesn’t greatly improve symptoms. In contrast, at the higher doses of current SNRI’s, the amount of extra dopamine made available does actually get larger.

As an example, somebody taking Cymbalta 60mg will have only a very small amount more dopamine available. That same person taking 90mg or 120mg may have quite a bit more extra dopamine, which can cause nervousness or anxiety.

Every drug has a different behaviour at different doses, which is known as the dose-response curve.

Take Action!

Are you on Wellbutrin and experiencing anxiety? Ask your doctor about reducing or removing the Wellbutrin, and see if it helps your anxiety. If so, will you still need to find something else to replace it?

Are you on an SNRI and experiencing anxiety? Particularly if it’s a higher dose, talk to your doctor about the possibility of going down to a lower dose and seeing it it makes a difference. If it does reduce your anxiety, and the lower dose isn’t enough to help with your other symptoms, you may end up discussing a switch to another antidepressant, or something else to augment the lower dose of your current SNRI.

There are lots of other reasons you may be anxious, which I’ll have more to say about in a future post, but these two kinds of medication-induced anxiety seem to very commonly get missed.