"Today I’m in the miraculous position of being one year sober," Dunham, 32, shared Wednesday alongside a photo of herself giving a thumbs-up.
"I've done a lot of cool things in this life, but none has brought me the peace, joy and lasting connections that being part of a sober fellowship has.
Life is full of problems, but the cool thing about this one is that there is a solution: in every city, in many countries, you can find a group of people who are working hard to live sober," she continued.
The actress said she "had an issue with drugs for a long time" but said that it took her a while to come to that realization because she was "outwardly successful" and the drugs were prescribed to her by a doctor.
"But wouldn’t you say that hurting people you love is an issue? Wouldn’t you say feeling lost and lonely much of the time is an issue? Wouldn’t you say wearing shorts to a movie premiere *is* an issue?" she posed.
"Sobriety hasn’t fixed my world. Life is still challenging," Dunham said. "I don’t need to escape this beautiful carnival. Instead, I’m on the ride. Please remember you are never too far gone, too broken or too unique. There are people in plain sight waiting to help you. Let’s do this."
The "Girls" creator previously revealed on Dax Shepard’s podcast, "Armchair Expert," in October that she misused the anti-anxiety drug Klonopin.
She spoke about how she quit the drug after becoming too dependant on it after she reached a point where she couldn’t function or feel normal without having the medication in her system.