You’re standing in the kitchen. Suddenly, you’re shouting. Or maybe you’re at a wedding and you start sobbing during a toast given by someone you barely know. Later, when the dust settles and your heart rate finally slows down, you ask the same question everyone eventually asks: I don't know what came over me.
It’s a bizarre feeling. It is like someone else took the wheel of your brain for five minutes while you watched from the passenger seat. Psychologists actually have a name for this. They call it an "amygdala hijack." It sounds like something out of a sci-fi flick, but it’s actually a very grounded, biological survival mechanism that occasionally malfunctions in the modern world.
We like to think we are rational creatures. We aren't. Not really. Most of the time, we are just emotional engines wearing a very thin coat of logic. When that coat gets ripped off, things get messy.
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The Science of the Hijack
Your brain is a layered cake of evolution. At the very bottom, you've got the brainstem, which handles the basics like breathing. Then you have the limbic system, where the amygdala lives. This tiny, almond-shaped cluster is your internal alarm system. It’s been around for millions of years. Its only job is to keep you alive.
When you perceive a threat—whether it’s a tiger in the brush or a passive-aggressive email from your boss—the amygdala reacts instantly. It doesn't wait for permission. It triggers a flood of hormones, mostly cortisol and adrenaline. This happens way before your prefrontal cortex, the "thinking" part of your brain, even realizes there is a problem.
This is why you might snap at your partner before you’ve even processed what they said. The signal hit the amygdala first. The "rational" brain was still putting its shoes on while the "emotional" brain was already out the door and halfway down the street.
Dr. Daniel Goleman popularized this concept in his work on emotional intelligence. He noted that the amygdala can actually bypass the neocortex. In a split second, your body is prepared for a fight, a flight, or to freeze in place. The problem? Our brains haven't quite figured out that a mean comment on Instagram isn't the same thing as a physical predator.
When Stress Becomes a Background Hum
Sometimes, it isn't one big event. It’s the "death by a thousand cuts" scenario. You’ve been working sixty-hour weeks. The dog is sick. The car is making that weird clicking sound again. You feel fine, or so you tell yourself, but your nervous system is redlining.
This is chronic stress. It lowers your threshold for a hijack. When you're already at a level nine, a level two problem will push you over the edge. You end up saying something you regret, and then you spend the next three days apologizing because you genuinely don't recognize the person who was yelling. Honestly, it’s exhausting.
Why "What Came Over Me" Happens in Relationships
Relationships are the ultimate breeding ground for these moments. Why? Because the people closest to us know exactly where our buttons are. Sometimes they press them on accident; sometimes they don't.
When we feel rejected or misunderstood by a partner, it triggers a "social pain" response in the brain that looks almost identical to physical pain on an fMRI scan. Your brain thinks you are being physically wounded. So, it fights back.
You might experience "flooding." This is a term coined by Dr. John Gottman, a famous researcher who spent decades watching couples interact in his "Love Lab" at the University of Washington. Flooding is when your heart rate goes above 100 beats per minute during a conflict. Once you're flooded, you literally cannot process information effectively. You lose your ability to be creative, to empathize, or to use humor. You are just a defensive animal trying to survive.
If you've ever looked at your spouse and felt a sudden, inexplicable surge of rage over a dirty dish, that’s it. That’s the flood. You aren’t actually mad about the dish. You’re reacting to a perceived lack of respect or a feeling of being overwhelmed, and your amygdala is sounding the sirens.
The Role of "Shadow" Traits
The Swiss psychiatrist Carl Jung talked a lot about the "Shadow." These are the parts of ourselves we don't like—the anger, the selfishness, the jealousy—so we push them down into the basement of our subconscious.
But things in the basement don't stay there. They ferment.
When you say, "What came over me?" you are often seeing a glimpse of your Shadow. It’s that part of you that you’ve tried to ignore, finally bursting through the floorboards because it’s tired of being hidden. It’s not that you were possessed; it’s that a part of your own psyche finally took the mic.
Acknowledging this is step one. If you pretend that "angry you" doesn't exist, "angry you" will continue to hijack the car. If you admit that you have the capacity for that kind of intensity, you can start to catch it before it takes over.
Can You Stop It?
Sort of. You can’t stop the amygdala from firing. It’s too fast. But you can widen the gap between the impulse and the action.
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Viktor Frankl, a psychiatrist and Holocaust survivor, famously said that between stimulus and response, there is a space. In that space is our power to choose our response.
The goal isn't to never feel that surge of emotion. The goal is to notice the surge and decide not to act on it immediately. This is harder than it sounds. It requires "interoception"—the ability to feel what is happening inside your body.
Physical Cues to Watch For
- Your chest feels tight or hot.
- Your jaw clenches.
- Your breath becomes shallow and fast.
- Your vision narrows (tunnel vision).
- You feel a sudden "buzzing" or restlessness in your limbs.
If you feel these things, you are in the "danger zone." Your brain is preparing to hijack you.
Practical Tactics for Real-Time Control
Forget the generic "just breathe" advice for a second. While breathing helps, you need a toolkit that actually disrupts the neural feedback loop.
The Temperature Shock
If you feel a massive emotional surge, splash ice-cold water on your face. This triggers the "mammalian dive reflex," which naturally slows your heart rate and resets your nervous system. It’s a hard physical override for an emotional state.
The 5-4-3-2-1 Technique
Force your prefrontal cortex back online by making it do work. Name 5 things you can see, 4 you can touch, 3 you can hear, 2 you can smell, and 1 you can taste. This forces your brain to shift from "survival mode" to "observation mode."
The 20-Minute Rule
If you are "flooded" during an argument, you must stop. Physically leave the room. But here is the catch: you can’t spend those 20 minutes rehearsing your comeback. If you sit there thinking about how wrong the other person is, you’ll stay flooded. You have to do something else. Read a book, watch a stupid video, or go for a walk. It takes the body at least 20 minutes to chemically clear the adrenaline and cortisol from your system.
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Label the Feeling
Literally say it out loud or in your head: "I am feeling a surge of rage right now." Studies from UCLA show that labeling an emotion reduces the activity in the amygdala. It’s called "affect labeling." By putting a name on it, you move the experience from the emotional centers of the brain to the linguistic/rational centers.
Making Sense of the Aftermath
So it happened. You lost it. You said the thing. You cried the tears. Now what?
The worst thing you can do is dive into a shame spiral. Shame just creates more stress, which makes you more likely to get hijacked again tomorrow. Instead, look at the event like a scientist.
What were the "vulnerability factors"? Were you hungry? (Hunger legitimately impairs the prefrontal cortex). Had you slept less than six hours? Was there a specific word or phrase that triggered you?
Most people find that their "what came over me" moments follow a pattern. Maybe you always lose it when you feel ignored. Maybe you snap when you feel trapped. Once you identify the pattern, the mystery disappears. It’s not a ghost in the machine; it’s just a specific program your brain runs when it feels threatened.
How to Move Forward
Understanding the "why" is great, but changing the "how" is where the work is.
Start by practicing "low-stakes" mindfulness. You don't need to meditate on a mountain for three hours. Just try to notice your breath while you're sitting in traffic. Notice the feeling of the steering wheel. If you can learn to pay attention to your body when you’re calm, you’ll have a much better chance of noticing when your body starts to rev up during a conflict.
Talk about it with the people in your life. Instead of just saying "sorry," explain the process. "I got overwhelmed, my brain went into fight-or-flight mode, and I reacted poorly. I’m working on noticing that feeling earlier." This builds trust and helps others understand that your outburst wasn't necessarily a reflection of how you feel about them, but rather a reflection of your own internal stress state.
Actionable Next Steps:
- Identify your primary physical "tell." Everyone has one—a hot neck, shaky hands, or a stomach knot. Pinpoint yours today.
- Establish a "Safe Exit" phrase. With your partner or a close friend, agree on a phrase like "I'm starting to feel flooded; I need fifteen minutes." When that phrase is used, the conversation stops immediately, no questions asked.
- Check your "biostatics." If you find yourself frequently wondering what came over you, look at your sleep and caffeine intake. High caffeine and low sleep are a recipe for amygdala hypersensitivity.
- Practice "Name It to Tame It." Next time you feel a minor irritation, name it. "I am feeling annoyed that the light is red." Build the muscle of labeling emotions before the stakes are high.
Taking control of these moments isn't about becoming a robot. It's about becoming the boss of your own biology. You won't be perfect, but you can certainly stop being a passenger in your own life.