A time period during which someone in their teens and/or twenties (often female) starts dressing rebelliously and/or trashy, partying frequently, engaging in serious alcoholism and other hardcore substance abuse (cocaine, ecstasy pills, etc.), and racking up several misdemeanor (and sometimes even felony) charges for their behavior. The name "Lindsay Lohan phase" is a reference to former teen star Lindsay Lohan, who not only went through this phase for nearly 6 years in the late 2000s and early 2010s, but is arguably the most infamous person to go through such a phase. Though Lindsay Lohan is filthy rich and has nothing to worry about now that her days of being off-the-rails are over, non-celebrities that go through this phase aren't so lucky. The ones that don't die from their reckless behavior are often unable to get a good job once they've grown up due to their criminal record, even if it's been several years since they turned their life around. The answer to this problem is to remember that as much as your social life means to you, you have to make your future your number-one priority and say "no" to peer pressure.
Person 1: why has Lexi been so pissed off lately?
Person 2: She's in her late 20s and still can't get a stable, good-paying job because she went through a Lindsay Lohan phase in her early 20s.
Person 1: Damn, that must suck!