And, like with other drugs, your brain eventually develops a tolerance to self-harm, requiring more and more for you to get the same high. When I started, I would just scratch my arms without even drawing blood, and I could go for weeks without doing it again. Within two years, I was hurting myself for hours at a time, and even required stitches on one occasion. I once stepped into a public bathroom stall to self-injure at 8 p.m. The next time I looked at my watch, three hours had passed. I approached cutting my thigh with the same time-dilating attentiveness normally reserved for marathoning Orange is the New Black.
Since most people think of addiction as a chemical thing, this highlights the difference between an "addiction" and a "coping mechanism": Basically, coping mechanisms don't mess up your life. If you get into exercise or knitting, you can build sexy new biceps or a new sweater to cover those biceps with (those two coping mechanisms don't have a lot of synergy). But with an addiction like self-harm, you still "cope" with the immediate problem, but you also get loads of scarring, shame, and a new secret to keep from everyone around you.
And yes, there are withdrawal symptoms if you try to quit (another person with experience in self-harm I've spoken with describes tremors and headaches when they tried to stop). Endorphins function like heroin, so when you stop doing the thing that produces them, your body gets mad as hell and starts screaming for that metaphorical needle in your arm. It's been shown that treating victims of self-injury with endorphin-blockers magically makes them stop wanting to cut.
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