Can ADX be negative?

Could you please clarify for me if it's possible for the Average Directional Index, or ADX, to take on a negative value? I've been studying technical indicators and I've come across conflicting information regarding this. Some sources state that ADX ranges from 0 to 100, while others mention the possibility of negative values, which is quite confusing. I'd appreciate it if you could shed some light on this matter and explain the mechanics behind it, if indeed ADX can go below zero. Thank you in advance for your expertise and time.