Attention Deficit/ Hyperactivity disorder also known as ADHD is categorized by
Behavioral: aggression, excitability, fidgeting, hyperactivity, impulsivity, irritability, lack of restraint, or persistent repetition of words or actions
Cognitive: absent-mindedness, difficulty focusing, forgetfulness, problem paying attention, or short attention span
Mood: anger, anxiety, boredom, excitement, or mood swings
Also common: depression or learning disability
ADHD is said to begin its effects on children ages 4-6, and was even admitted that, "You might not notice it until a child goes to school." 
Naturally, children are buoyant and full of energy, ready to explore and learn, to brand a child with an Attention Deficit disorder at such a young age is a stunt in growth and a setup for future failure. Not only are these children being branded with a disorder, they are also being medicated to suppress the normal activity of the brain. "If your child is 4 or older and you’ve tried behavioral therapy for at least 6 months without much change, you can also try low-dose ADHD medication."
Attention Deficit and difficulty focusing they say, but what exactly should children as young as 4-6 be focusing on? The Bible tells us, "Train up a child in the way he should go: and when he is old, he will not depart from it." Prov 22:6. The counsel here is evident that the responsibility of the training and the development of the child's early years rests on the parents, especially the mother, for fitness in this life and the life to come. How, then should a child be trained.
The First Eight or Ten Years.--"Children should not be long confined within doors, nor should they be required to apply themselves closely to study until a good foundation has been laid for physical development. For the first eight or ten years of a child's life the field or garden is the best schoolroom, the mother the best teacher, nature the best lesson book. Even when the child is old enough to attend school, his health should be regarded as of greater importance than a knowledge of books. He should be surrounded with the conditions most favorable to both physical and mental growth.It is customary to send very young children to school. They are required to study from books things that tax their young minds. . . . This course is not wise. A nervous child should not be overtaxed in any direction." 
This overtaxing of the mind by entering into school at a young age is what causes the symptoms we see in ADHD. Development of the body and mind happens in stages and children attending school at a young age are forced into stages that they are not ready for. Piaget's Cognitive Stages of Development states that children between the ages of birth to 7 years, are in the Sensorimotor and Preoperational Stages.
In the Sensorimotor Stage (Birth-24 months)
During the early stages, infants are only aware of what is immediately in front of them. They focus on what they see, what they are doing, and physical interactions with their immediate environment. Because they don't yet know how things react, they're constantly experimenting with activities such as shaking or throwing things, putting things in their mouths, and learning about the world through trial and error. The later stages include goal-oriented behavior which brings about a desired result.
Between ages 7 and 9 months, infants begin to realize that an object exists even if it can no longer be seen. This important milestone -- known as object permanence -- is a sign that memory is developing.
After infants start crawling, standing, and walking, their increased physical mobility leads to increased cognitive development. Near the end of the sensorimotor stage (18-24 months), infants reach another important milestone -- early language development a sign that they are developing some symbolic abilities. 
In the Preoperational Stage:
During this stage (toddler through age 7), young children are able to think about things symbolically. Their language use becomes more mature. They also develop memory and imagination, which allows them to understand the difference between past and future, and engage in make-believe.
But their thinking is based on intuition and still not completely logical. They cannot yet grasp more complex concepts such as cause and effect, time, and comparison. 
The Child's Program During Infancy.--"During the first six or seven years of a child's life, special attention should be given to its physical training, rather than the intellect. After this period, if the physical constitution is good, the education of both should receive attention. Infancy extends to the age of six or seven years. Up to this period children should be left, like little lambs, to roam around the house and in the yards, in the buoyancy of their spirits, skipping and jumping, free from care and trouble.
Parents, especially mothers, should be the only teachers of such infant minds. They should not educate from books. The children generally will be inquisitive to learn the things of nature. They will ask questions in regard to things they see and hear, and parents should improve the opportunity to instruct and patiently answer those little inquiries. They can in this manner, get the advantage of the enemy and fortify the minds of their children by sowing good seed in their hearts, leaving no room for the bad to take root. The mother's loving instruction at a tender age is what is needed by children in the formation of character." 
Lessons During the Transition Period.--The mother should be the teacher where every child receives his first lessons; and these lessons should include habits of industry. Mothers, let the little ones play in the open air; let them listen to the songs of the birds and learn the love of God as expressed in His beautiful works. Teach them simple lessons from the book of nature and the things about them; and as their minds expand, lessons from books may be added and firmly fixed in the memory. But let them also learn, even in their earliest years, to be useful. Train them to think that, as members of the household, they are to act an interested, helpful part in sharing the domestic burdens, and to seek healthful exercise in the performance of necessary home duties.
It Need Not Be a Painful Process.--Such a training is of untold value to a child, and this training need not be a painful process. It can be so given that the child will find pleasure in learning to be helpful. Mothers can amuse their children while teaching them to perform little offices of love, little home duties. This is the mother's work--patiently to instruct her children, line upon line, precept upon precept, here a little, and there a little.
And in doing this work, the mother herself will gain an invaluable training and discipline.
Morals Imperiled by School Associates.--Do not send your little ones to school too early. The mother should be careful how she trusts the molding of the infant mind to other hands.
Many mothers feel that they have not time to instruct their children, and in order to get them out of the way, and get rid of their noise and trouble, they send them to school. .
Not only has the physical and mental health of children been endangered by being sent to school at too early a period, but they have been the losers in a moral point of view. They have had opportunities to become acquainted with children who were uncultivated in their manners. They were thrown into the society of the coarse and rough, who lie, swear, steal and deceive, and who delight to impart their knowledge of vice to those younger than themselves. Young children, if left to themselves, learn the bad more readily than the good. Bad habits agree best with the natural heart, and the things which they see and hear in infancy and childhood are deeply imprinted upon their minds; and the bad seed sown in their young hearts will take root and will become sharp thorns to wound the hearts of their parents. 
If left to these devices of overtaxing the minds of young children, the inevitable result is to bring about disease. one can as well, run the risk of losing their child/ren in this life and the possibility of next.
Prevention is better than cure.
 White, Ellen, Child Guidance, page 300
 White, Ellen, Child Guidance, pages 301-302