View Full Version : Heredity and Environment

07-30-14, 02:16 PM
I believe that ADD can be better understood if we examine people's lives, not only bits of DNA.

Heredity does make an important contribution, but far less than usually assumed.

At the same time, it would serve no purpose to set up false opposition of environment to genetic inheritance.

No such split exists in nature, or in the mind of any serious scientist.

If in this book I emphasize environment, I do so to focus attention on an area that most books on the subject neglect and none explore in nearly enough detail.

Such neglect frequently leads to crippling deficiencies in what people are offered by way of treatment.

-Gabor Mate M.D., "Scattered", P25.

In the first paragraph of Introduction page, in the book "Scattered" (a discussion about the origin and treatment of ADHD), Dr.Mate encourages..

"a reasoned discussion of how environment and heredity might mutually affect the neurophysiology of children growing up in stressed families.."

The amount and density of norepinephrine and dopamine producing cells originating in the brainstem/midbrain areas, are strongly influenced by personal experiences throughout life, especially during critical sensitive periods of early development.

This thread is meant to encourage "a reasoned discussion of how environment and heredity might mutually affect the neurophysiology of children growing up in stressed families.."


07-30-14, 02:52 PM
..Research indicates that each implementation of SR (and hence EF) across all types of SR (working memory, inhibition, planning, reasoning, problem-solving, etc.) depletes this limited resource pool temporarily such that protracted SR may greatly deplete the available pool of effort.

This results in an individual being less capable of SR in subsequent situations or immediately succeeding time periods and thus more likely to experience problems or fail outright in their efforts at SR and resistance to immediate gratification.

Such temporary depletions may be further exacerbated by stress, alcohol or other drug use, illness, or even low levels of blood glucose.


07-30-14, 03:11 PM
In the human infant, the growth of dopamine-rich nerve terminals and the development of dopamine receptors in stimulated by chemicals released in the brain during the experience of joy, the ecstatic joy that comes from the perfectly attuned mother-child mutual gaze interaction.

Happy interactions between mother and infant generate motivation and arousal by activating cells in the midbrain that release endorphins, thereby inducing in the infant a joyful, exhilarated state.

They also trigger the release of dopamine.

Both endorphins and dopamine promote the development of new connections in the prefrontal cortex.

Dopamine released from the midbrain also triggers the growth of nerve cells and blood vessels in the right prefrontal cortex and promotes the growth of dopamine receptors.

A relative scarcity of such receptors and blood supply is thought to be one of the major physiological dimensions of ADD.

Gabor Mate M.D., "Scattered", P 83.

i!i i!i

07-30-14, 03:16 PM
THE AREAS OF THE CORTEX responsible for attention and self-regulation develop in response to the emotional interaction with the person whom we may call the mothering figure.

Usually this is the birth mother, but it may be another person, male or female, depending on circumstances.

Although for the sake of convenience, I will at times refer to this person only as the mother, the word should always be understood to refer to whoever the primary nurturing figure may be--father, mother, or grandparent, foster parent or adoptive parent of either gender...

Gabor Mate M.D., "Scattered", P 69.

i!i i!i

07-30-14, 03:37 PM
People with ADD are hypersensitive.

That is not a fault or a weakness of theirs, it is how they were born.

It is their inborn temperament.

That, primarily is what is hereditary about ADD.

Genetic inheritance by itself cannot account for the presence of ADD features in people, but heredity can make it far more likely that these features will emerge in a given individual, depending on circumstances.

It is sensitivity, not a disorder, that is transmitted through heredity.

In most cases, ADD is caused by the impact of the environment on particularly sensitive infants.

Sensitivity is the reason why allergies are more common among ADD children than the rest of the population.

It is well known, and borne out again and again in clinical practice, that children with ADD are more likely than their non-ADD counterparts to have a history of frequent colds, upper respiratory infections, ear infections, asthma, eczema and allergies, a fact interpreted by some as evidence that ADD is due to allergies.

Although the flare-up of allergies can certainly aggravate ADD symptoms, the one does not cause the other.

They are both expressions of the same underlying inborn trait: sensitivity.

Since emotionally hypersensitive reactions are no less physiological than the body's allergic responses to physical substances, we may say truthfully that people with ADD have emotional allergies.

Gabor Mate M.D.,"Scattered", P 59.

i!i i!i

07-30-14, 04:44 PM
Most polygenetic traits are partially influenced by the environment.

For example, height is partially influenced by nutrition in childhood.

If a child is genetically programmed to be average height but does not get a proper diet, he or she may be below average in size.

Other examples of environmentally influenced traits are mental illnesses like schizophrenia and depression.

A person may be genetically predisposed to have depression, so when that person's environment contributes major stresses like losing a job or losing a close relative, the person is more likely to become depressed.