Sources familiar with the situation tell TMZ ... those close to Paris suggested rehab after what law enforcement says was a suicide attempt over the weekend, landing her in the hospital. We're told the attempted suicide shows some serious underlying problems ... they say Paris is dealing with all sorts of emotional issues as well as substance abuse issues.

Our sources say Paris' team had help ready to spring into action Sunday, but she refused.

TMZ broke the story ... Paris slit her wrists and was rushed to a hospital early Saturday morning, where she was placed on a temporary 5150 hold. We're told she's been distraught ever since "Leaving Neverland" began airing.

As to why Paris was released just hours after she was hospitalized, our sources say she told the hospital that had admitted her that her lawyers were taking her to UCLA Medical Center, and the hospital let her go with the attorneys, but she never ended up at UCLA.

Paris is almost 21 -- she's an adult, and therefore the decision to check into rehab is hers and hers alone.