Dopamine
It is too simplistic because not everyone who has too much dopamine or too little serotonin develops a disease, and because factors other than neurotransmitters influence those diseases.
There isn't an opposite of ADHD par say. Schizophrenia would be the chemical opposite of ADHD since it involves too much dopamine in the brain as opposed to little dopamine in individuals with ADHD.
if there too little water animal die crops are not growing and if their is too much water flood came
You die
it can have effects on your memory
Too little cholesterol level IS dangerous in its effect on hormone secretions.
Insufficient levels of dopamine can cause problems with sleep, mood and movement. For example, lack of dopamine causes the muscular problems seen in people with Parkinson's disease.
Stuff.
you eat cake
become dyhydrated
A recession happens .