SSRIs are the most widely used class of psychiatric medications, helpful for depression, anxiety, OCD, panic, PTSD, anger, and certain personality disorders (Why should the same drug treat all these things? Great question!) They’ve been pretty thoroughly studied, but there’s still a lot we don’t understand about them.

The SSC Survey is less rigorous than most existing studies, but its many questions and very high sample size provide a different tool to investigate some of these issues. I asked fifteen questions about SSRIs on the most recent survey and received answers from 2,090 people who had been on SSRIs. The sample included people on all six major SSRIs, but there were too few people on fluvoxamine (15) to have reliable results, so it was not included in most comparisons. Here’s what we found:

1. Do SSRIs work?

People seem to think so:

Made me feel much worse: 6% Made me feel slightly worse: 7.4% No net change in how I felt: 23.7% Made me feel slightly better: 41.4% Made me feel much better: 21.4%

Of course, these statistics include the placebo effect and so cannot be taken entirely at face value.

2. Do some SSRIs work better than others?

I asked people to rate their experience with the medication, on a scale from 1 to 10. Here were the results:

Lexapro (356): 5.7 Zoloft (470): 5.6 Prozac (339): 5.5 Celexa (233): 5.4 Paxil (126): 4.6

Paxil differed significantly from the others; the others did not differ significantly among themselves. In a second question where participants were just asked to rate their SSRIs from -2 (“made me feel much worse”) to +2 (“made me feel much better”), the ranking was preserved, and Lexapro also separated from Celexa.

This ranking correlates at r = 0.98 (!?!) with my previous study of this taken from drugs.com ratings.

I don’t generally hear that Paxil is less effective than other SSRIs, but I have heard that it causes worse side effects. The survey question (probably wrongly) encouraged people to rate side effects as “negative efficacy”. My guess is that the difference here is mostly driven by side effects.