The TV star only just discovered that she has the disorder - which the NHS says "is a condition that affects people's behaviour" and can make people restless, have trouble concentrating and act on impulse.
A clip was played on the ITV programme that showed Sawalha, 58, being told that the symptoms she exhibited were consistent with ADHD.
Raising one hand to her face, the presenter became tearful as she said: "I don’t know why that makes me cry, sorry."
Sawalha said that after learning she had ADHD there were a lot of things in her life that she wanted to forgive herself for.
She told her fellow panellists that when she had broken down in tears it was because she was trying to accept that there could be a reason behind the "chaos" in her life.
The star also urged viewers to get checked out if her story resonated with them, sharing that she was doing well.
Fans of the ITV show flocked to Twitter to say how brave Sawalha was for opening up.
"So proud of you," one person tweeted.
Another posted: "Good on you @nadiasawalha talking about your ADHD diagnosis."
Another said: "I have ADHD, work as an ADHD specialist nurse, my kids have ADHD. I have worked really hard and currently completing my masters in advance clinical practice.
"When you understand it..it becomes a strength."
"Thank you for speaking openly about this Nadia," said somebody else. "Many women will gain reassurance from your honesty."