The voice in my head is an asshole. — Dan Harris

I've always assumed that habits were just physical things: the habit of washing your hands before eating; the habit of smoking cigarettes after sex; the habit of checking your phone first thing in the morning. Recently I learned that there are mental habits, that some of them are bad habits, and that those bad habits can be broken.

It's normal to reflect on your past to learn from your mistakes. This is a good mental habit. But when you're spending hours every day thinking about the same past event, that's a bad mental habit known as rumination.

Let’s say you had an argument with a friend at a party. The next day in the shower you think: 

“If only I had said this, then he would’ve agreed with me!” 

That's normal. You’re processing the event. But if you begin thinking about it all day long, and even the next day, then you're no longer reflecting and have veered into the territory of rumination. Clearly this event was important for you—that’s why your brain wants to review it repeatedly to make sure you didn’t miss any details. But eventually there's no more analysis that can be done and your brain can get stuck in review mode. When that happens, it can actually damage your health.
 

Why ruminating is bad for your health

Personally, the longer I allow myself to ruminate, the more aggressive my inner voice becomes:

“If only I had said this, then he would’ve agreed with me! 
…
And if I wasn’t such an idiot then I would’ve thought of that. 
…
God, why am I so fucking stupid??”

According to Dr. Ethan Kross in his book Chatter: The Voice in Our Head, Why It Matters, and How to Harness It, this type of self-shaming actually worsens our health:

When our internal conversations activate our threat system frequently over time, they send messages to our cells that trigger the expression of inflammation genes, which are meant to protect us in the short term but cause harm in the long term. 

This happens because our cells interpret the experience of chronic psychological threat as a viscerally hostile situation akin to being physically attacked.

Unfortunately, you can’t change what happened in the past, and ruminating on it just makes things worse. But there is a way to break this mental habit!
 

How to stop ruminating

Recurring ruminative thoughts are like a toddler whining for candy. If you give in to her demands, it teaches her that whining works to get your attention, and so she’ll whine more. 

• Similarly, allowing yourself to endlessly engage in ruminative thoughts legitimizes them as normal, and consequently those thoughts increase in frequency because they know they can effectively grab your attention.

Good parents know that saying “no” to a child is important to their development because they learn that you're willing to set boundaries and will enforce them. But how you say “no” is equally important. Telling the child to “shut up”, or neglecting their request entirely, creates a poor relationship with your child. 

• Equivalently, you shouldn’t be mean to ruminative thoughts or neglect them, because that can cause them to fight back.^[1]

Instead, gently telling the toddler, “it's before dinner, candy would ruin your appetite,” lets her know that you acknowledge her request and that you see her, but you will not give in to her demands. She may whine at first, but if you maintain your resolve, then she’ll learn that whining doesn’t work. 

• In the same way, ruminative thoughts want to be acknowledged and know that you see them, but you don't have to engage with them.

My ruminations typically happen with respect to my dating life. When I go on a date and it doesn't work out (when I was hoping it would), my mind immediately goes into detective mode: what did I miss? did I make any mistakes? what could I do better next time?

These are all helpful questions, but only in moderation. 

Even after I think deeply on the matter for 20-30 minutes, the rest of the day (and the next day, and the next…) my brain keeps returning to the date and wants to solve something that is unsolvable—which is to change the past.

I've learned to do two things to help stop ruminations:

1. I analyze the event in as much depth as possible by journaling about it.
2. After that, throughout my day when I start having thoughts like, “what if I had said this?”, I say to that thought, “thanks for showing up, but I’m ruminating. I've already journaled about this.”
   1. And it works! The ruminative thought goes away…for about 30 seconds. Like the toddler, ruminative thoughts really want to make sure that you’re 100% resolved in your conviction.

When I first started doing this practice of labeling thoughts (which comes from Cognitive Behavioral Therapy), I would have to stay vigilant all day long to ensure that I don't slip into ruminating, and thankfully by the next day my brain would quiet down. Nowadays after a date that doesn’t work out, and after I journal about it, I label any lingering negative thoughts as ruminations which quickly go away once I show them that I’m not going to engage with them.

Eventually my brain moves on and thinks about other stuff, just like how the toddler eventually gives up on her demands for candy when you keep gently telling her “no”. 

1. ^{^}

   Metacognitively, the worst thing you can do is to actively suppress your thoughts. Saying, “I don't want to think that thought anymore!” doesn't work, and can paradoxically increase the frequency of that thought. It’s similar to if someone told you, “don’t picture a pink elephant for the next five minutes!” Well, you’re probably going to picture a pink elephant as soon as they say that.

   I didn't know this when I was 19 years old. Back then I had an intrusive thought so disturbing, that I immediately tried to suppress it—to memory-wipe myself from ever having thought it. That really doesn't work. My brain tortured me by blasting that thought on repeat for a year straight. The more I tried to suppress it, the more frequently it would come up. It was only when I finally acknowledged the thought, discussed it with a trusted friend, and journaled about it, that the thought finally went away.