There are some people who have autistic traits or have autism. They can look normal, attend school normally and go to work as per normal. However, they might be more sensitive to changes in colour, texture and sounds. These people might also experience meltdowns more frequently.
Sometimes, they are just "not happy" and are unable to express their feelings, or even realise that they are not happy until the meltdown. These conditions can be diagnosed by a psychologist or psychiatrist trained in autism. You may like to seek treatment if you notice you or your family members having these behaviours.
