It is called “emotional dysregulation” and it is an autistic trait.
Autism, Meltdowns, and the Struggle to Manage Emotions
I never heard of “the equivalent of Aspergers Syndrome” but if the psych says he has it that is a good reason to suspect Autism.
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Professionally Identified and joined WP August 26, 2013
DSM 5: Autism Spectrum Disorder, DSM IV: Aspergers Moderate Severity
“My autism is not a superpower. It also isn’t some kind of god-forsaken, endless fountain of suffering inflicted on my family. It’s just part of who I am as a person”. - Sara Luterman