Co-occurrent conditions, also known as co-morbidities are overlapping conditions that often come hand-in-hand with one another.
There are many overlapping traits and symptoms in neurodivergent conditions, so much so that some experts say that in the next decades, many of them will be merged into one group. It is possible to get multiple diagnoses because of this. 1
For example, the co-morbidities for ADHD include PMDD (in people who menstruate), autism, OCD, learning difficulties (like dyslexia), SPD (sensory processing disorder).