Finding the right antidepressant often takes a special combination of perseverance and patience, which is why it's so frustrating to finally land on a treatment plan only to have it stop working years later. But it turns out that building up a tolerance to these types of medications is possible and probably more common than you think. It even happened to Sarah Silverman, she shared on Instagram this week.

Silverman has been open in the past about her experience with depression and once said that she has been on antidepressants since she was 13. But, on Monday, she told fans that she hit a rough patch with her treatment.

“I’ve officially built a tolerance to Zoloft and for some reason the subsequent free fall looks fucking great on me. #SilverLinings,” she captioned an Instagram photo featuring a close-up of her face.

Plenty of people sympathized in the comments. “I've gone through the Zoloft and other med tolerance and subsequent lack of efficacy,” one person wrote. “It really sucks hitting that point with a medication that actually worked for a bit.”

Another commenter said: “I am in the exact same position right now after a while of being as healthy as I’ve been in a decade I feel the darkness encroaching. It’s like I’m standing on a cliff edge looking down and I know what’s at the bottom and it’s not pretty. I’m terrified that every time I feel well it will end.”

Antidepressants can be lifesaving for people who experience anxiety and depression, but some people do find their medication becomes less effective over time.

In general, antidepressants alter the levels of neurotransmitters, like serotonin and dopamine, in the brain. Exactly how this causes mood changes isn't totally understood at this point, but we do know that, for some people, adjusting the levels of these neurotransmitters can improve depression and anxiety symptoms. Because it can take a long time for those changes to happen, you might have to wait several weeks for a noticeable difference in your mood.

And while it doesn't happen to everyone, some people notice that their antidepressants don't work as well after a while, Gail Saltz, M.D., a psychiatrist and the author of The Power of Different: The Link Between Disorder and Genius, tells SELF. This is referred to as the “poop out” effect, or antidepressant tolerance (aka tachyphylaxis), according to the Mayo Clinic.