I don't think I've ever experienced shutdowns. I only ever got outbursts (which are now controlled by antidepressants), and panic attacks.
When I had an outburst it was usually because I was so wound up by something or overwhelmed by negative emotions that I just freaked out. I'd shout, scream, hit myself in the face, slam doors as hard as I could, cry, swear, and argue with loved ones. So I was very verbal. I just didn't know what else to do when feeling all these negative emotions at once.
I still have panic attacks from time to time despite being on antidepressants, but that's OK because panic attacks don't upset others like outbursts do. When I'm having a panic attack it starts with a sudden urge to cry, racing heart, chest pains, difficulties catching my breath, headaches and the need to be comforted by other people. Some people have accused me of attention-seeking before but although I crave empathy when having a panic attack it is still genuine and not crocodile tears.
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Female