Sunmi confessed that she was diagnosed with a borderline personality disorder.

The new episode of Mnet's 'Running Mates' that aired on December 16th showed the continuation of the girls Sunmi, EXID's Hani, Oh My Girls' YooA, Chung Ha, and LOONA's Chuu sharing their inner thoughts with one another.

On this day, Sunmi said, "It's right for you to take a break if things are hard. The time I took a break was when I left Wonder Girls. At that time, it was more heartbreaking than my body hurting. I made my solo debut and joined Wonder Girls again, but I was given much time to think and I think those times I had to think to myself ate me away."

Sunmi then confesses carefully, "I was diagnosed five years ago with a borderline personality disorder. That's what was bothering me, but I felt relieved because I got diagnosed and can get treatment, and I got better after taking medicine. Still, I had to resolve the fundamental thing because it's the people around the person with a borderline personality disorder that goes through a lot of difficulties" and began shedding tears.

She continued to say, "Probably that was the time I really had to stop briefly. To be honest, we debuted so young and started our life in society. We spent our time in a car during the age when the sense of oneself even formed. That's why it's more important for us to look back at ourselves and ask what do we like to do, what we are good at. It's also important for us to cater to our own emotions. So I started to realize a little bit that I passed puberty, and I'm better now. I decreased my medication." Then Sunmi added, "I'm strong, no I became stronger."

Meanwhile, borderline personality disorder refers to a serious mental illness characterized by instability in moods, interpersonal relationships. Symptoms include emotional instability, feelings of worthlessness, insecurity, impulsivity, and impaired social relationships.