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The Impact of Addiction on the Child’s Brain
Children’s Health Day
Dr. Dawn-Elise Snipes PhD, LPC-MHSP
AllCEUs Counselor Continuing Education

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– Brain development and critical periods
– Impact of exposure to alcohol, opioids, nicotine, cannabis, and stimulants on the fetal brain
– Impact of exposure to alcohol, opioids, nicotine, cannabis and stimulants on the developing brain (0-24)

Bonsai and the Brain
Prenatal Exposure
– Most drugs of abuse easily cross the placenta and can affect fetal brain development. In utero exposures to drugs thus can have long-lasting implications for brain structure and function. These effects on the developing nervous system, before homeostatic regulatory mechanisms are properly calibrated, often differ from their effects on mature systems.
– In the fetus the drugs can impact blood flow to the placenta, can increase stress hormones can act directly on the neurological mechanisms of the fetus
Brain Development and Critical Periods
– Critical early events are the closure of the neural tube around day 22 of embryonic life and neurogenesis, which is complete by 16 weeks
– During the second half of gestation, nerve cells in the neocortex are generated and migrate to the appropriate brain regions
– Elevated prenatal psychological and biological stress signals repeatedly have been linked to
– Hypothalamic-pituitary-adrenal (HPA) axis dysfunction and fearful temperament and also to internalizing and externalizing behavioral problems in childhood and adolescence
– The affected regions were associated with higher cognitive functions including reasoning, planning, attention, working and recall memory, language, and social and emotional processing.

Brain Development and Critical Periods
– The developing organism makes adjustments based on the predicted postnatal environment.
– “Fetus exposed to an impoverished intrauterine environment will prepare for, and perhaps thrive in, a postnatal environment of nutritional scarcity. However, if that same fetus is instead born into an environment of nutritional abundance, its developmental adjustments may result in an increased risk for obesity, diabetes, and cardiovascular disease”

Fetal Exposure
– People who are pregnant show a decline in physiological and behavioral responses to stress during the third trimester, including a dampened cortisol response, decreased blood pressure, heart rate, and catecholamine responses to psychological and physical challenges
– Injury or deprivation of environmental input occurring at specific stages of postnatal life can dramatically reshape the underlying circuit development, which becomes increasingly more difficult to correct later in life.
– The brain’s physical structures are set around age 6. But during adolescence, different parts of the brain form hundreds of millions of connections.
– Frontal cortical development is later in adolescence and likely contributes to refinement of reasoning, goal and priority setting, impulse control and evaluating long and short term rewards
Fetal Exposure
– Alcohol
– Alcohol exposure appears to affect the timing and pattern of nerve cell generation, both delaying the process and altering the number of cells that are produced.
– Early, heavy exposure leads to the most severe outcomes and is associated with mental retardation, sensory deficits, and motor problems
– Unusual cell formations can be observed in many areas in the brain, including the hippocampus (learning, memory, fight or flight), cerebellum (motor activity), and neocortex (sensory perception, motor activity, spatial reasoning)
– Fetal Alcohol Spectrum Disorders
Fetal Exposure
– Nicotine
– Nicotine readily passes through the placenta, and fetal concentrations of these compounds are significantly greater than those achieved by the mother
– Exposure to nicotine through maternal consumption (smoking or NRT) or second hand smoke disrupts the cholinergic system, a key modulator of brain development, and alters synaptogenesis, neuronal migration, neurotransmitter release
– Newborns exposed in utero to nicotine are more irritable, have poorer attention, exhibit hypertonicity, increased tremors and startle responses, poorer self-regulation than unexposed infants
– Children exposed to nicotine in utero months show increases in externalizing behaviors as young as 18–24
Fetal Exposure
– Nicotine
– A study of 3-year-olds exposed to tobacco in utero determined that increases in oppositional behavior were correlated to third trimester exposure
– Children age 6 and younger exposed prenatally had decreased receptive language skills, increased likelihood of ADHD
– 16-18 year olds exposed in utero exhibited cognitive deficits (an effect that appears to be withdrawal induced—Second hand smoke in school-aged children) and increased impulsivity
– Prenatal exposure to nicotine greatly increased the risk of later tobacco use and SUD
Fetal Exposure
– Cannabis
– THC can cross the placenta with reasonable efficiency
– Endogenous cannabinoids are crucial for proper development in utero, and exogenous cannabinoids such as marijuana alter fetal growth trajectories
– Newborns exposed to marijuana exhibit sleep disturbances, altered responses to visual stimuli and increased startles and tremors which persist through age 3
– Prenatally exposed school aged children exhibit deficits in executive function and verbal and memory tasks
– 6–year-olds showed attention deficits, elevated impulsivity, and hyperactivity, deficits in short-term memory and verbal reasoning
– Elevated levels of D2 receptor transcript in the amygdala of males suggests potential for altered emotional regulation

Fetal Exposure
– Cannabis
– Even in their early 20s, exposed individuals still have deficits in working memory and impulsivity
– Prenatally exposed children were also more likely to experiment with marijuana at an earlier age use more frequently
– Some studies have shown that exposure to THC during the second trimester may result in increased heroin-seeking behavior in offspring

Fetal Exposure
– Opioids
– Opioid receptor expression and endogenous opioid concentrations in the fetus and neonate differ from that in adults
– Exposure to opiates in utero and childhood may have more distinctive effects compared with adult exposure
– At the pre- and elementary school ages, prenatally exposed children show motor and cognitive impairments, inattention and hyperactivity
– Deficits in spatial learning and memory may be tied to hippocampal cholinergic alterations
– The ACOG (2012) recommends opioid maintenance therapy as the first line of treatment for opioid dependence during pregnancy since illicit opiate use is associated with poor prenatal care, nutrition, and fetal health
– Prenatal buprenorphine may produce fewer neurobehavioral problems
– Naltrexone exposure during pregnancy should usually be avoided as it significantly impacts endogenous opioid systems in utero
Fetal Exposure
– Stimulants
– Affect the serotonin (5-HT) system and activate the reward system by triggering a massive release of dopamine (DA) (Especially sensitive in the second trimester)
– Brain changes in exposed neonates include abnormal brain development closely resembling that in oxygen deprived infants including altered density or in the white matter
– Decreases in size of certain brain regions, including the putamen (learning) and hippocampus (learning and memory) correlated with poorer sustained attention and verbal memory
– There are more than 100 white matter disorders that are associated with cognitive or emotional dysfunction
– Prenatal amphetamine exposure was associated with externalizing behavioral problems at 5 years
Child and Adolescent Exposure
– Maturational changes are regionally-, age-, and sex-dependent, and occur in different brain regions at different times.
– Numerous alterations in dopamine pathways during adolescence
– Early/mid-adolescent exposure may be especially likely to affect social behavior, reward sensitivity, and affect regulation
– Late adolescent exposures may be more likely to disrupt cognitive tasks dependent on more slowly developing PFC systems

Exposure in Youth and Adolescents
– The most common alterations reported across substance used are in the frontal lobe which is the last region to complete development
– Adolescence is a time of neurobiological development and increased propensity to seek out novel stimulation and engage in risk-taking behaviors which can alter development (like a bonsai)
– The frontal lobes (executive functioning), and limbic/hippocampal circuitries (learning and emotion regulation), have been identified as regions particularly vulnerable to exposure to physical and emotional stressors during adolescence
– Due to high rates of alcohol and drug co-use, including marijuana, nicotine, and other substances, it has been difficult to attribute abnormalities to any one substance in particular

Exposure in Youth and Adolescents
– Alcohol and Cannabis
– Studies that have demonstrated timing-specific exposure effects, with different patterns of lasting consequences after exposures during early-mid adolescence than late-adolescence/emerging adulthood including long-lasting social anxiety and increased risk of later AUD
– Heavy alcohol drinking reduced the rate of brain growth in proportion to amount of daily consumption
– Alterations were reported in the structure of the frontal lobe (emotional expression, problem solving, memory, language, judgment), temporal lobe (processing affect/emotions, language, auditory learning) and parietal lobe (language processing) in current adolescent alcohol and cannabis users

Exposure in Youth and Adolescents
– Alcohol and Cannabis
– Adolescent marijuana and alcohol users who were abstinent had persistent alterations in the thickness of the Frontal Anterior Cingulate Cortex which is involved in attention, reward seeking, decision-making, impulse control and emotion regulation
– Adolescent marijuana users show deficits on behavioral tasks of working memory, long-term memory, attention and impulse control
• Adolescent alcohol users show poorer performance than non-drinkers on tasks of attention and executive functioning. Self-awareness, Inhibition, working memory, emotional regulation, motivation, planning and problem solving.

Exposure in Youth and Adolescents
– Nicotine
– Brain volume alterations relative to nicotine dependence severity (mg/day) are consistently shown
– Altered attentional processing (especially in withdrawal)

– Like a bonzai tree there are times when the brain is developing and malleable.
– The brain begins development in the first trimester and continues until age 24.
– During adolescence different parts of the brain develop at different times (different branches of the tree)
– An insult to the immature brain can cause much more dramatic changes because of its malleability (sapling vs. hardened branch)
– All drugs appear to alter parts of the brain associated with learning, memory, emotion regulation, planning and problem solving and impulse control.