My definition of health would be the balance of mental, physical and emotional well-being. Anything that disrupts this balance, unnaturally, is considered an illness. An illness is also anything that can be treated. You can be given medications, go through surgical procedures, therapy of some sort etc. An illness is an imbalance that can be treated to bring you back to a healthy state. I think my general understanding of these terms is influenced by society and what we were taught in school and in part cultural influence. We were always taught that someone that is healthy is a person with physical strength, eats well and is emotionally stable. All illnesses were medically treated, like a disease. You have to go to the doctor, and take your medications in order to become healthy again.
Insomnia- is an illness. Lack of sleep causes mental imbalance and can lead to physical illness. Without sleep, your body does not function at its best ability. In a sense, an individual with Insomnia is like a zombie. Their bodies are in total imbalance. People who have insomnia can eventually die without treatment.
ADHD- Although, people with ADHD look to be physically healthy, they are mentally and emotionally imbalanced. They don’t have the attention span of normal healthy individuals and tend to be a little emotionally unstable. Individuals with ADHD are given medications to calm them and give them the attention span of a healthy person. Therefore, ADHD is an illness.
Migraines- they can be normal just like a headache, are very common. They may be considered a minor imbalance. However, migraines can be so severe that they can cause imbalance physically and mentally and occur often. There are many treatments that help get rid of these migraines, like medications. Therefore, Migraines are considered an illness.