"As many of you know, around a year ago I revealed that I have lupus, an illness that can affect people in different ways," the 24-year-old pop star explained.
"I've discovered that anxiety, panic attacks and depression can be side effects of lupus, which can present their own challenges."
"I want to be proactive and focus on maintaining my health and happiness and have decided that the best way forward is to take some time off," she continued. "Thank you to all my fans for your support. You know how special you are to me, but I need to face this head on to ensure I am doing everything possible to be my best."
"I know I am not alone by sharing this," Gomez concluded. "I hope others will be encouraged to address their own issues."
A source close to the former Disney star tells ET the break comes after Gomez said she "hadn't felt like herself" lately, and that it is "absolutely not related to alcohol or substance abuse."
"She decided to clear her calendar for the year in order to have this be her priority for future happiness and didn't want to leave any promoters at bay," the source continued. "She feels relieved that she can now make more sense of why she was feeling the way she was and is optimistic about the future."
Upon hearing the news, the official Lupus Research Alliance tweeted well-wishes to Gomez. "Sending our very best to @selenagomez," the message read. "Thank you for being such a strong voice for the #lupus community."
According to the organization's co-CEO and co-president, Kenneth M. Farber, "it is not commonly known that depression, anxiety and panic attacks can be side effects of lupus."
"We are so proud of Selena for taking care of herself and bringing awareness to this sometimes very misunderstood illness," he added.
While chatting with Billboard last October, Gomez announced she had been diagnosed with the chronic inflammatory disease three years ago, which caused her to take a break from the spotlight and undergo chemotherapy.
"I wanted so badly to say, 'You guys have no idea. I'm in chemotherapy. You're a**holes,'" Gomez said at the time, referencing rumors that she was dealing with substance abuse issues. "I locked myself away until I was confident and comfortable again."
Now, she's not afraid to speak out on the disease she'll be living with for the rest of her life.