The transition team of NYC Mayor-elect Bill de Blasio took the unusual step today of releasing a video featuring his 19-year-old daughter, Chiara de Blasio, in which she describes her battle with depression and drug and alcohol abuse.

“Every kid who grows up in New York grows up pretty fast; it’s astonishing,” she says, before describing a struggle with clinical depression that lasted throughout her adolescence.

“It made it easier, like, the more I drank and did drugs, to share some common ground with people that I wouldn’t have,” Chiara continues. “It didn’t start out as a huge thing for me, but then it became a really huge thing for me.”

The teenager says she thought that going away to California for college (at Santa Clara University, where she is an environmental studies major) would help her leave her troubles behind, but instead, her use of alcohol and marijuana only intensified.

Chiara says she received support from her parents, especially incoming First Lady Chirlane McCray, who did “every little thing she could.” She eventually got treatment from a therapist and at what she describes as an “outpatient” facility in New York City.

“Removing substances from my life opened so many doors for me. I was able to participate in my dad’s campaign, and that was the greatest thing ever,” Chiara says.

“…Getting sober is a positive thing. And it’s not easy, by no means is it easy. It’s the hardest thing I’ve ever done. But it’s so worth it.”

The video, released on Christmas Eve day, came in an email from Bill and Chirlane de Blasio with the subject line “Chaira’s story.”

“As parents, our instinct has been to protect our daughter and privately help her through a deeply personal struggle,” the couple wrote.

“But not only has Chiara committed to her own health, she is also committed to helping young people everywhere who face similar challenges.”

“Her courage to speak out demonstrates a wisdom and maturity far beyond her 19 years, and we are grateful every day for her commitment to lifting up those who need to know that they are not alone.”

At the end of the video, words appear across the screen urging anyone watching who believes they have a substance abuse problem to seek help, and also offering a website: “ok2talk.org.”

UPDATE: The NYT notes that during the campaign, de Blasio aides repeatedly refused to answer questions about Chiara’s rumored drug abuse or answer questions about whether she was receiving treatment.