https://medium.com/age-of-awareness/adhd-is-so-much-more-than-inattention-and-hyperactivity-13-lesser-known-symptoms-of-attention-ffab2f03c86a

“Some of the lesser known symptoms of ADHD are:

• Rejection Sensitive Dysphoria (RSD) refers to the experience of extreme emotional sensitivity and pain caused by the belief that you have been rejected or criticized.
• While many people experience hyperactivity, people also can experience an inability to relax, which can be hell, especially in waiting situations where the lack of mental stimulus can make a person feel completely trapped.
• Finding words for what they are feeling is another struggle. Alexithymia and dyslexithymia refer to the inability to find any words or the accurate word to match their feelings, respectively.
• Flash emotions are when one’s feelings change without any opportunity to think, react, or feel. People cannot filter their response or process; they just suddenly feel intense emotion.
• People with ADHD sometimes have headaches more frequently than neurotypical people, especially men. Some researchers attribute this to the stimulation of dopamine receptors, while others link it to higher stress levels.
• Many people with ADHD also have a Delayed Sleep Phase Syndrome (DSPS), which means they have an untypical circadian rhythm. The average adult functions best on a sleep cycle where they sleep from 11 pm to 7 am, but people with DSPS tend to function on a 2 am to 10 am schedule best.
• Object permanence, or the concept that objects continue to exist even when you can’t see them, is often a difficult ability. It’s not that they do not understand the concept; they know things still exist. They just become less consciously able to keep track of those items. This is why people with ADHD often lose items or forget to do tasks without visual reminders and structured routines.
• Although usually associated with Autism Spectrum Disorders, self-stimulating behaviors, or stimming, is something people with ADHD do too.
• Due to several characteristics of ADHD, like forgetfulness, sensory sensitivity, time distortion, and organizational challenges, personal hygiene can be tough for some people to maintain. For many of the same underlying reasons, disordered eating and poor money management skills are also quite common.”