STRESS EARLY IN LIFE AND ITS IMPACT ON AUTISM by Rami Serhan

EARLY LIFE STRESS & AUTISM

2010

IMPACT OF STRESS ON NEWBORNS: Nothing breaks a parent’s heart more than seeing her child suffer from depression or live isolated because of anxiety or develop debilitating diabetes or worse die a sudden death from a heart attack. However the origins of all these problems of ageing stem - in large part - from the way parents handle their newborn children. Most of this book is dedicated to laying out the parameters for proper handling of sensitive children. However, let us begin with some of the consequences of mishandling a newborn baby. IMMEDIATE CONSEQUENCES OF STRESS: It is true that minimal, short-lived, pleasant stress otherwise known as stimulation can help children refine their personality since birth. However, unpleasant or longer-lived stress may have adverse consequences at any age. Most of the immediate consequences of stress are adaptive in the sense that these changes are geared towards ensuring the person’s survival. However, not all the measures of the stress response are fit for today’s civilization concept of survival, especially for autistic children. Classic animal studies [by Michael Meaney group in McGill university and others] show that rat puppies that are heavily licked and groomed by their mothers grow up to have a better ability to handle stress than puppies who are only sparingly groomed. In addition, puppies that are mildly stimulated [as in taken away from the mother for 15 minutes daily] also grow up to be better prepared at handling stress later in life. Animal studies also show a generational link. Puppies who well groomed as youngsters grow up to groom their own puppies well. Puppies that are neglected or abandoned as youngsters grow up to repeat similar behaviors as adults and their offspring typically have even greater difficulties handling stress. It is without a question that this process is many folds more complicated in human babies. Let us begin by examining the immediate consequences of stress on babies. Increased vigilance: A very common example of that is someone who is visibly startled every time a car back fires and every time someone throws a fire cracker or even every time someone enters the room unannounced. Most insensitive babies may not notice when these things happen or

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will take them as an exciting, thrilling thing to watch and interact with. A sensitive baby, on the other hand, will react immediately to such a sudden change in environment. A sensitive baby faced with a change in her environment will act alarmed, anxious and will direct all her senses in full attention to examine that and any other possible change. A sensitive baby will consider such a change as a threat to her existence and will become on alert for any unfamiliar movement, noise, flash or disturbance. Indiscriminate focus: Distributed focus is an immediate consequence of unexpected change in environment. This is the opposite of narrow constricted focus (hyperfocus) which usually ensues with longer standing or more severe stress. During stress, one of the adaptive aspects of vigilance is that sensitive babies tend to focus on the whole environment and surroundings. They tend to distribute our attention equally to anything that moves or hums or glitters… part of vigilance is expecting danger to be coming from any direction or source. While this is protective if one is in the jungle at night hiding from a tiger, it may not be the same in today’s world. The indiscriminate focus is a manifestation of the non-screening quality of sensitive babies preventing them from focusing for example on the one person who just entered the bedroom. This usually leads to awkward interaction with this person. The baby looks frazzled, subdued, inattentive and unwelcoming. There is usually either no discernable facial expression or a sad frowning disposition. Distributed focus makes it very difficult for the baby to make a connection. It also slowly turns people off, including sometimes the parents, from interacting since the baby’s response does not reinforce opposing party’s behavior. It is during these first six months of life that sensitive babies begin to miss out on learning facial features and body language of others. Learning while alarmed: During stress, as attention has to be distributed to all the surroundings, focused attention on a specific task such as learning becomes very difficult to accomplish. A stressed baby cannot pay sufficient attention on one source of stimulation to learn a movement or a gesture or the means to handle a toy. This process of indiscriminate focus occupies the working memory of the baby and prevents her from retaining cues presented to her by others. For example, every time a chair moves, she has to bounce a moving chair against the concept (symbol) of chair in her mind in order to determine that the chair is neutral and not dangerous. This constant need to rule out multiple sources of danger tends to

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consume the working memory and deprives the stressed kid from the opportunity to listen to or watch what others are doing. The presented material is deprioritized automatically since it is not essential for survival at a threatening time. Constructive learning requires either pleasant stimulation from a familiar, consistent face or higher level of stress sufficient to recruit more mental capacity and promote a shift to narrow focus. Remember the pattern of response to stress under the behavioral curve ball tradition. Fear learning: During stress, while constructive learning of non-survival matters is suppressed, fear learning is enhanced. Fear learning is essential for survival since it is meant to keep us away from the lion’s den – literally - or from where the mammoth elephants hung out. However in today’s world where, stress often comes from an unruly sibling or grandma entering the baby’s bedroom, there is no point in facilitating a fear path that leads the stressed kid to avoid the source of “danger”. Yet, it happens so often, and sensitive kids end up narrowing their circle of interaction as a result of repetitive stress coming from even the closest people in their life. These fear pathways are easily reinforced with every stressful episode and the part of our brain inherited from reptiles favors their learning. Neither kids nor adults going through these processes can will themselves naturally to prevent them. These are very old, very well entrenched processes rooted in our instincts. Fear learning may result in an expanding preference for avoidance over social engagement. Inhibition of growth: During stress, the metabolic priorities are inverted. While during quiescent times, one may engage in pleasurable and leisurely activities, during stress, the only purpose is survival. This means that the focus of the body during stress is solely on keeping the heart beating and the brain working, among few other essential functions. The focus is lifted away from building muscle or brain tissue or bone or any other activity aimed at furthering the baby’s growth and development but is not immediately essential for survival. Growth, whether physical or intellectual, is stifled until the threat is resolved. Some of that results from the stress hormones inhibiting or antagonizing growth hormone, insulin, melatonin and other leisurely hormones. We will come back to these hormones and many more later. Reduced appetite:

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Most people can relate to the fact that after a fender bender, it might take some time before one can engage in eating or other self-fulfilling activities. The same applies to children in distress too, especially the sensitive ones. Increased cardiovascular tone: The increase in heart rate, blood pressure and tone of the blood vessels is part of the preparations for the fight or flight reaction during stress. This may also be associated with emptying of the bladder and defecation to get rid of the extra weight. This may explain, at least in part, the reason why many sensitive kids have toilet training problems or may regress after successful toilet training. These are all adaptive changes in the forest where we need to run or wrestle a fox, but are practically useless when the source of stress is noise coming from the next room where a sibling is training on a guitar. Besides, these changes in the heart and blood pressure may have long-term health consequences. Table: Some lasting and often permanent effects of adverse early life events [immediate stress] on a newborn’s stress response later in life: Change

Effect

1- Increase hypothalamic CRH

Increase stress reactivity & anxiety

production 2- Increase amygdala CRH

Increase stress reactivity & fear

production

learning

3- Decrease cortisol receptors in

Increase difficulty terminating stress

hippocampus & hypothalamus

response

4- Decrease GABAA receptors in

Increase difficulty terminating the

hippocampus

stress response

5- Increase brain noradrenalin

Increase reactivity to stress &

activity

irritability

6- Increase serotonin availability &

Difficulty gaining dominance over

utilization

personal life

All these effects cumulatively result in limiting the baby’s potential later in life; often these effects result in a life marred by desperation, perpetual failure and loss of self-esteem.

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LEGEND: This table was compiled from many sources, some of which appear in the references section at the end of this chapter. CRH: corticotropin releasing hormone GABAA: gamma aminobenzoic acid receptor type A These are some of the major effects of early life stress with a significant impact on how stress is handled later in life. There is plenty of evidence from both animal and human studies illustrating that higher magnitude of stress exposure early in life increases the vulnerability to stress later. This comes in the form of excessive and more prolonged responses to stress. In fact the exaggerated stress response may translate into a limited potential at large in one’s life due to increased likelihood of depression. Moreover, these disadvantages are carried to and built upon with future generations. LONG TERM CONSEQUENCES OF STRESS: Prolonged activation of the stress system or frequent activation thereof, usually leads to our adaptive mechanisms turning on us and pushing us toward chronic illness and debilitating diseases later in life. Prolonged increase in heart rate and blood pressure, eventually can lead to hypertension, and atherosclerosis (narrowing of blood vessels). Increased blood viscosity during stress may contribute to strokes and heart attacks and deep vein thrombosis. The increased viscosity is originally designed to limit bleeding in the case of injury. Still, later in life many more problems are associated with continuous or repetitive stress including weight gain, loss of stamina, insulin resistance, diabetes, depression, anxiety, cancer, increased cholesterol and LDL cholesterol… you get the picture. Who is at the most disadvantage in developing all these consequences? It is the person who responds more vigorously to stress and the person who undergoes too much stress. Many times both conditions are fulfilled in the sensitive person. There is only limited room in this book for more in-depth explanation of how the diseases of ageing can be a consequence of long standing stress since conception.

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TABLE: COURTESY MEANEY, MICHAEL J. et al. ANNALS OF THE NEW YORK ACADEMY OF SCIENCES 1999; 896: 66-84 [MODIFIED] SUMMARY OF THE MAJOR METABOLIC EFFECTS OF STRESS-INDUCED INCREASES IN ADRENALIN & CORTISOL: Target tissue or system

Biologic effect

Functional/clinical correlate

Liver

Increased glucose synthesis

Increase blood sugar levels

Liver

Decrease HDL production

Increase cholesterol in blood

Muscle and fat

Glycogen & protein

Increase blood sugar levels

breakdown to form glucose Muscle and fat

Fat breakdown and

Enhanced reliance on fatty

mobilization to blood

acids for fuel – facilitator of obesity & ageing

Muscle and fat Heart and blood vessels

Decrease sensitivity to

Facilitate insulin resistance

insulin actions

– a precursor to diabetes

Increase heart rate and

Increase blood pressure,

blood vessel tone

blood vessel wall thickening and risk of blood clots

Growth axis

Decrease GH release*,

Delay in growth and

tissue sensitivity to GH,

development in children;

IGF1 and IGF2

bony frame; reduced tissue regeneration

Reproductive system

Inhibition of reproductive

Sexual maturity problems

hormones including LH,

at puberty, cycle

progesterone &

irregularities,

testosterone; render

premenstrual cramping,

target tissues resistant

reduced fertility, hot flashes, low libido

Thyroid axis

Decrease triiodothyronine,

Delay in growth and

the active thyroid

development in children;

hormone;

decrease metabolic rate

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EARLY LIFE STRESS & AUTISM Inhibition of TSH, shortterm only Skeleton Gastrointestinal

Reduced new bone

Osteopenia & osteoporosis

formation

– both genders equally

Inhibit stomach acid;

Bloating, food

reduce movement of food

fermentation, loose stools,

along;

constipation, irritable bowel, pain,

Gastrointestinal

weaken gut immune

free access of ingested

defenses; increase

toxins and food additives

permeability (leaky gut);

to rest of body;

weaken friendly bacteria

succumbing to microbes

in colon

including yeast and parasites.

Childhood stress

Further sensitizes stress

Increase likelihood of

pathways

anxiety and depression for the rest of life

HDL: high density lipoprotein; GH: growth hormone; IGF1 & 2: insulin like growth factors working to implement some of the functions of GH; TSH: thyroid stimulating hormone; LH: luteinizing hormone; * Inhibition of GH release is applicable to longer-standing stress after an initial short phase of potentiation.

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