The 38-year-old reality TV star is reportedly concerned for Scott, who has been spotted partying with various different women over recent weeks.
A source said: "Kourtney is worried for Scott, as are Scott's friends and the whole Kardashian family. They are really worried for him.
"They aren't angry – just concerned – because he's clearly going through something."
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Scott, 34, has recently been romantically linked to the likes of Bella Throne, Chantel Jeffries and Maggie Petrova.
But the Kardashian family feel Scott's recent behaviour is a function of his own unhappiness, which has reportedly been triggered by Kourtney dating model Younes Bendjima.
Another source told Us Weekly: "The partying and photos emerging are symptomatic of situations they've had in the past with him where he has been in a really bad place, mentally."
Kourtney Kardashian & Scott Disick. Picture: Instagram
Earlier this month, meanwhile, Scott admitted to being a " horrible sex addict".
The TV star revealed he's addicted to love-making during a candid conversation with Kris Jenner, Khloe Kardashian, Kim Kardashian West and his ex.
Speaking on 'Keeping Up with the Kardashians', Scott confessed: "I'm a sex addict. I'm a f***ed up, horrible sex addict."
Scott acknowledged his problem after he angered the Kardashians by bringing another woman with him on a family vacation in Costa Rica earlier this year.
Kourtney confronted Scott about the decision, calling his behaviour "disrespectful".
She said: "On a family vacation, don't you think it's inappropriate and disrespectful?
"To me, to your kids and to all my family? There's a level of respect and appropriateness that should just be known, but apparently, it's not."
Kourtney also rubbished Scott's explanation, accusing him of "playing the victim".