Autism

The entire list of mental disorders is made up - people have just grouped certain symptoms together and gave them an invented name. This can be useful for categorizing and treating people, but ultimately your mind is your own and nobody can really say what's going on inside. I have diagnosed myself and find categorizing myself as autistic useful - although I hate the idea that whatever goes on in my brain is considered a disorder, so I prefer the term neurodivergent. I'd use official diagnoses where they are useful for getting help and support, but always take them with a grain of salt. Psychiatry is not an exact science and both diagnosis and treatment are often not much more than trial and error.

Be especially careful when you are a person who has every reason to be angry about something in their life and someone tries to diagnose you with something like "Is-angry-for-no-good-reason" disorder, as it used to be the case of women suffering from 'hysteria' and abused teenagers getting diagnosed with personality disorders.