Lamar Odom -- Trashes His Father, Praises Kardashians As His 'ONLY Family'

Lamar Odom is breaking his silence to rip his own father to shreds for claiming that Khloe Kardashian and her mother drove Lamar into crack addiction -- and he's also acknowledging, for the first time, he's in a "dark" place.

In the scathing message Lamar says, "How can a man who has NOT once called me to check on my well being have the nerve to talk so recklessly about his own 'son'. He is my downfall!"

Lamar's angry letter, posted on Twitter, is a response to a published interview with Lamar's father, Joe Odom, in which he claimed the Kardashians cursed Lamar, ruined his career, and put so much pressure on him that he turned to drugs.

Joe also called Kris Jenner "an evil bitch."

Lamar's retort to his dad -- who's also battled drug addiction -- continues, "I have let this man and many others get away with a lot of s**t. He wasn't there 2 raise me. He was absent ALL of my life due to his own demons."

And Khloe's estranged husband fiercely defends her family, saying ... "He disrespecting the ONLY FAMILY that has loved me without expecting anything in return. They are the ONLY ones that have been here consistently 4 me during this dark time."

By "dark time" he could mean separation from Khloe, but as we've been telling you ... Lamar is deep in the grips of drug addiction -- so it could also be his first public admission of that battle.

Lamar added ... his father's "demons may be the ONLY thing he gave 2 me."

As for his current struggles -- addiction, marriage, basketball career -- Lamar says, "Only person 2 blame is myself. Say what you want about me but leave the ones who have done nothing but protect and love me out of this!"