Kate Gosselin is telling a very different story than her son Collin about the mental health facility she sent him to.

In his best-selling memoir, "In the Shadow of Eight: Surviving the Reality of My Childhood," Collin writes that his mom sent him to a behavioral health facility in 2016 ... when he was just a pre-teen.

Collin recalls his 2-year institutionalization, claiming Kate had only visited him once that entire time and told him he "broke" the family.

But Kate's denying the accusation in a TikTok comment, writing ... "I visited EVERY single time the facility felt he was stable enough for a visit. Sometimes a visit was planned but the facility canceled it because he was too unstable and it would have to be rescheduled."

She also claimed that she tried to get in touch with her son "every single time" he had phone privileges, and alleges Collin's "violent behavior" was the reason he was in the facility in the first place.

As you know, Collin also accused Kate of abusing him as a child ... including one time when she allegedly bound his hands and feet with zip ties.