I wa trying to figure out that about Lauren too. The Beginning of the Bad was when she found the DVD of max and Stacey. That then made her the catalyst (in her eyes) for the first break down of the family.
Then max was a twat and she ended up trying to kill him, which landed her in juvenile detention and then in the care system for a while I think? Then she came back and max was a twat, max was a twat again and her mum got off with her uncle, roxys lover and then married a dullard while max disappeared and her half brother died.
It's not pleasant but it's nothing compared to, say, whitneys life.