PSYCH 3AB3 - Adolescent Psych

What is Adolescents?

• cultural phenomenon describing the period beginning at puberty and ending in adulthood.

• defined differently by culture.

• ~age 10-18.

Emerging Adulthood

• ages ~18-25.

• as more individuals are depending on parents financially and emotionally.

Developed World

• 20% of world pop. accounts for 50% of world’s income.

  • disparity. 

Developing World

• 235 million children (6-18) have no access to school.

• global literacy and mathematics have been declining globally (as of 2019)

  • 44% min. proficiency in math.

  • 24% can read.

    • big disparity for gaining knowledge.

Globalization & phones

• 70% of world pop. has smartphones.

• 8 billion ppl in the world → 7 billion smartphones.

Bicultural Identity - Globalization

• one to align with local traditions and practices, and one to align with preferred online community.

Global Adolescent Community & Biases

• majority of empirical research on adolescents is conducted in the West.

  • only a small portion (12%) of global adolescents (10-19) are from the West.

• majority of adolescents reside in India and South Asia (28%), Asia (25%) and Sub-Saharan Africa (20%).

Historical Insights on Adolescents

• across the board it has been said that they have no rational thought or restraint at this age.

• similar to modern conceptions.

CDC Youth Risk Survey (2021)

• there has been a decline in the % of high school students engaging in risky behaviour.

  • risky behaviour: sex and alcohol.

    • from ~50-65% in 1991 → ~25-30% in 2021.

Defining the Beginning of Adolescents

• with better prenatal and early years care (healthcare, nutrition, parental awareness) → puberty is beginning earlier than ever (~10-12 y/o).

Defining the End of Adolescents

• more students going to high school and college/university → adult obligations (financial independence, marriage, parenting) begin later. 

Adolescents and Adulthood are…

• cultural constructs.

  • there is no definitive line (start or end).

Criteria for Adulthood

• accepting all responsibilities for oneself.

• making independent decisions.

• being financially independent.

• culturally specific:

  • military service, supporting family, supporting parents, marriage.

The Scientific Method Steps (simple)

1. A curiosity

2. Collect the evidence

• detail in methodology is critical.

3. Draw Conclusions

Age of First Smartphone/tablet and Mental Wellbeing (Sapien Labs 2013)

• higher scores (better) associated with later ownership.

• bigger impact on females compared to males - overall lower scores regardless of time of ownership.

• correlational not causation.

Correlation examines the relationship between…

• two existing variables.

  • naturally occurring.

Possible Explanations for Sapien Lab’s Experiment

• parents more likely to give smartphones to children who are struggling → in attempt to help.

• parents who don’t have time for their children → smartphones used as a distraction → leading to poor MH.

  • lost opportunity for real life experiences or are the phones harmful?

• parents who can afford smartphones → have kids who struggle more.

The Experimental Method

• form a hypothesis.

• testable hypothesis.

• create two groups:

  • experimental & control.

Smartphones & Mental Health Hypothesis

• “smartphones cause harm to youth.”

  • a study like this would be unethical b/c you’re trying to cause harm.

    • turn the question around to make it testable.

Smartphones & Mental Health Testable Hypothesis

• “stopping smartphone use improves mental wellbeing.”

  • experimental group: stop use for two weeks.

  • control group: continue use for two weeks.

Perrault et al. (2019) → Sleep & Vigilance Study

• youth (12-19)

• 2-week baseline phase of measuring evening & sleep habits.

• 40-minute sleep education workshop.

• 2-week intervention phase: no screens after 9pm on school nights.

Perrault et al. (2019) → Sleep & Vigilance Results

• data suggests that smartphone use before bed disrupts sleep.

• faster reaction time in phase 2 → no smartphones after 9pm.

• *off-screen activities before bed don’t correlate with sleep duration.

Kleemans et al. (218) → Social Media & Body Image Study

• 144 adolescent girls (14-18).

• experimental group: 10 digitally altered instagram photos.

• control group: 10 original instagram photos.

• DV: body image scale & Iowa-Netherlands Comparison Orientation Measure.

Kleemans et al. (218) → Social Media & Body Image Results

• girls with lower social comparison showed no change in body image ratings after viewing the altered or unaltered images.

• girls with higher social comparison showed lower ratings of body image after viewing the altered images compared to the girls who viewed the original images.

Functional Significance - Body Image

• is the girl with a body image of 4.6 really upset about her body image?

• the worry comes when girls have very low ratings (e.g., 0-2).

  • at high risk of developing ED, depression, etc.  

Statistical Significance - Body Image

• p < .05

• there’s less than a 5% chance that the results are by chance.

• 95% chance this is a statistically significant finding.

Kleemans et al. (218) → Successful Manipulations

• participants rated altered photos →

  • more likely to have used filters.

  • but also rated them more pretty and attractive.

Questionnaire → Research Methods

• advantages: large sample, quick data collection.

• disadvantages: preset responses, no depth.

Interview → Research Methods

• advantages: individuality & complexity.

• disadvantages: time and effort of coding.

Observations → Research Methods

• advantages: measure actual behaviour.

• disadvantages: being observed may change behaviour.

Biological Measurements → Research Methods

• advantages: precise data.

• disadvantages: expensive, relation to behaviour may not be clear.

Experiments → Research Design

• advantages: control, identification of cause & effect.

• disadvantages: may not reflect real life.

Natural Experiments → Research Design

• advantages: shows relation among naturally occurring events.

• disadvantages: unusual circumstances, rare.

Ethnographic Research → Research Design

• advantages: entire span of daily life.

• disadvantages: researcher must live among participants, possible bias.

Case Studies → Research Design

• advantages: rich, detailed data.

• disadvantages:difficult to generalize results.

Correlational Design → Research Design

• advantages: quick & inexpensive.

• disadvantages: correlations difficult to interpret.

The Adolescent Brain

• myelination improves efficiency.

• unused synapses get pruned.

Why are Adolescents so Reckless?

• puberty involves remodelling of dopaminergic system → leads to increased reward-seeking.

Risk-taking ______ in adulthood.

• declines.

  • b/c of even better cognitive control & self regulation.

Dopaminergic System Includes:

• acronym: ANOMS

• amygdala

• nucleus accumbens

• orbitofrontal cortex

• medial prefrontal cortex

• superior temporal sulcus

Social Information Processing:

• recognition of social stimuli, social judgements, social reasoning.

Dopaminergic System

• dopamine receptor density in striatum (basal ganglia) and prefrontal cortex starts around age 10.

• dopaminergic activity in PFC increases in early adolescence.

• note: dopaminergic changes observed in animal models even after gonadectomies (sex organs responsible for releasing sex hormones that start puberty) suggest no causal relationship with puberty.

Steinberg et al (2008) → Sensation Seeking Study

• sample of 935 individuals aged 10-30.

• self-reports on sensation-seeking.

• behavioural measures:

  • Tower of London task.

  • stoplight driving simulation.

Steinberg et al (2008) → Self-Report Results

• Self-reported impulsivity decreases with age.

• sensation-seeking peaks around 12-15 years.

Steinberg et al (2008) → Tower of London Results

• tested planning & executive functioning.

• with increasing difficulty, older participants took longer to make first moves → younger participants don’t change their behaviour

Steinberg et al (2008) → Stoplight Results

• measured number of intersections with a safe stop at the light.

• younger participants were more reckless than older ones.

• ages 16-17 were the most cautious.

  • perhaps because they had just gone through drivers training.

Adolescent Sensation Seeking

• brain areas implicated in self-regulation take longer to mature.

• consistent with heightened sensation seeking in adolescents and better impulse control with age (into adulthood).

Why are Adolescents so Reckless?

• subcortical limbic regions mature faster than prefrontal cortex.

  • emotional motivation matures before executive functioning.

• with developmental experience → functional connectivity between regions improves the control of the drives.

  • explains why adolescents are aware of risky vs. safe behaviour but still choose risky.

• risk-taking involves subcortical systems known to evaluate rewards.

  • look at the whole brain.

Maturation During Adolescence

• same areas showing largest changes from childhood to adolescence → were different when comparing adolescents to young adults.

• dorsal, medial, and lateral regions of frontal lobes showed large group differences.

• little change in parietal, temporal, and occipital lobes.

Brain Changes from Adolescence to Adulthood

• huge change in nucleus accumbens & prefrontal cortex.

• areas showing grey matter in adolescents → but white matter in young adults.

  • representing increased myelination.

Galvan et al. (1999) → Reward & Nucleus Accumbens Study

• 37 participants (7-29 years old).

• 3 cues associated with different reward values.

• respond as quickly as possible → click left or right finger to indicate side (L or R).

• correct answers → reward received.

• incorrect/no answer → no reward.

• monetary rewards.

Galvan et al. (1999) → Reward & Nucleus Accumbens Key Variable of Interest

• looking at brain activity in the 2 seconds before motor response.

Galvan et al. (1999) → Reward & Nucleus Accumbens Results

• adolescents showed more change than children and adults in nucleus accumbens (NA) (for largest reward).

• children showed greatest change in orbitofrontal cortex.

• larger reward → more neural responses.

• adults demonstrate learning across trials → faster reaction times & more strategic with how they use their energy.

• children showed no learning across trials.

Galvan et al. (1999) → Adolescents & Nucleus Accumbens Results

• depending on size of reward adolescents showed greatest variability in NA.

• not purposefully engaging in risky behaviour → reward just means more in their brain than it does to children or adults.

• NA reacts more readily if the stimuli represents a reward.

• showed some learning across trials.

Media Use & Brain Development in Adolescents

• highly sensitive to acceptance & rejection through social media.

• heightened emotional sensitivity & protractive development of frontal areas → makes them more reactive to emotion-arousing media.

• more aggressive after being rejected online.

  • possibly weaker emotion regulation until DLPFC matures.

Crone & Konijn et al. (2018) → Brain Activation & Peer Feedback Study

• used fMRI to test media imagery & peer feedback on neural activity.

• 24 females (18-21)

• rated sizes of bikini models → “too thin” or “normal”

• viewed peer feedback → “too thin” or “normal”

Crone & Konijn et al. (2018) → Brain Activation & Peer Feedback Experimental Method

• peer feedback would be shown after response was made.

• more often peer would disagree with participant.

• compare brain activity of:

  • incongruent trials → participant responded: “too thin” & peer responded: “normal”.

  • congruent trials → participant & peer responded: “too thin”.

    • consistent with idea that women should be thin.

Crone & Konijn et al. (2018) → Brain Activation Results

• increased activity in left & right insula and dmPFC, extending into anterior cingulate cortex (ACC).

  • ACC: impulse control

  • insula: emotion, self-awareness, cognitive functioning.

• these areas are more impacted in social media & peer-rejection/acceptance contexts.

Crone & Konijn et al. (2018) → Self Esteem

• more activity in all areas (left & right insula, dmPFC, & ACC) the lower the girls self-esteem.

• interpretation: girls with low self-esteem → peer feedback differing from their own matters more → triggers more neural activity to process → more impactful.

• not evident in other incongruent case → when participant said ‘normal” and peer said “too thin”

Endocrine System → Hypothalamus…

• signals hormones.

  • gonadotropin-releasing hormone production is increased (related to body fat).

  • fat cells produce protein leptin that provides signal to release GnRH.

Endocrine System → Pituitary Gland…

• releases gonadotropins.

  • follicle-stimulating & luteinizing hormones.

• poor thyroid functioning related to abnormalities in sexual development.

Feedback Loop

• Gonads (ovaries/testes) release sex hormones.

  • estrogen: estradiol

  • androgrens: testosterone

• hormone levels are detected and controlled by the hypothalamus.

Adrenocorticotropic Hormone (ACTH):

• causes adrenal glands to increase androgen production.

Sex Differences

• estrogens & androgens exist in both sexes.

• more sex-specific hormones are released as puberty progresses.

• 100 nanogram/decilitre = 1,000 picograms/mililitre

  • way more testosterone in the human body.

  • estradiol is a much more powerful hormone.

Estradiol

• spikes in girls during puberty.

Testosterone

• spikes in boys during puberty.

Menarches

• first menstrual period.

• mature egg released ~28 days; ~400 ova over the lifetime.

• first 4 years of ovulation is unpredictable.

Spermarche

• first production of sperm.

• 100~500 million sperm per ejaculation.

Primary Sex Characteristics

• egg & sperm production.

• bodily changes to support reproduction.

  • enlargement of penis & testes, vaginal organs, uterus, ovaries.

Secondary Sex Characteristics

• not directly related to reproduction but is triggered by puberty.

  • more hair, pubic included.

  • sweat glands increase production

  • deepening of voice

  • enlargement of breasts (needed for milk production). 

First Developments of Puberty

• Females:

  • pubic hair & breasts → ~8y/o

• Males:

  • pubic hair → ~10y/o

Growth Spurts → Females

• from first year of life, rate of growth rapidly slows down until growth spurt around 12 y/o → height levels out around 15 y/o.

Growth Spurt - Males

• from first year of life, rate of growth rapidly slows down until growth spurt around 14 y/o → height levels out around 17 y/o.

Sex Differences in Puberty

• girls start showing physical signs earlier than boys (~2 years).

• possible explanation for body image issues and social comparison.

Muscle Mass

• boys: higher increase compared to girls & peaks around age 17.

• girls: lower increase compared to boys & peaks around age 16.

Body Fat

• boys: remains relatively constant, with a slight increase around age 12.

• girls: steadily increasing with a spike around age 12 → continues to increases much higher than boys.

  • necessary to carry babies.

  • contributing to body image obsessions. 

Body Mass Index

• ratio of weight to height.

• Canadian Guidelines:

  • underweight: <18.5

  • normal: 18.5-24.9

  • overweight: 25-29.9

  • obese: 30+

• culturally arbitrary definitions → not meaningful numbers.

BMI Controversy

• not a direct measure of body fat → doesn’t account for muscle mass.

• doesn’t distinguish between men, women, or different ethnicities.

Obesity

• chronic, progressive, and relapsing disease.

• presence of abnormal or excess adiposity → that impairs health and social wellbeing.

Treating Obesity

• focus on establishing values and goals of treatment, foster self-efficacy, and provide non-judgemental, stigma-free clinical practice.

Adolescence Prevalence of Obesity

• 1% in 1975, 7% in 2016 (5-19 years old).

• weight among youth increasing in developing countries too.

Health Risks of Obesity:

• breathing, fractures, hypertension, insulin resistance.

Insulin

• hormone in pancreas that helps glucose in the blood to be metabolized as energy in muscle, fat, and the liver.

Diet Statistics

• 36% of adolescents in the US eat fast food daily.

  • African Americans & Latino adolescents more likely to consume fast food and drinks.

Exercise Statistics

• 9 year olds spend ~3 hours of physical activity/day.

• 15 year olds spend > 1 hour/weekdays and .5 hours/weekend.

Hereditary & Family Concordance in Obesity

• correlation coefficient b/t…

  • husband & wife: .10-.19 (have similar lifestyles).

  • siblings: .24-.34

  • DZ twins: .15-.42

  • MZ twins: .70-.88

• different genes control protein synthesis and function involved in appetite, energy expenditure, metabolism, and adipogenesis (creating adipose tissue).

Attard, Herring, Howard & Gordon-Larsen (2013) Puberty x Obesity Study

• longitudinal adolescent cohort 12,000 participants (~16 y/o) followed into adulthood (~28 y/o).

• overall presence of (risk factors of cardiovascular disease):

  • diabetes → 5.5%

  • hypertension → 26.4%

  • inflammation → 31.3%

Attard, Herring, Howard & Gordon-Larsen (2013) BMI x Diabetes

• BMI = 23, odds for diabetes was:

  • 2.35 if BMI increased 8 points during age 15-20 y/o.

  • 2.33 if BMI was 20 across entire study period.

  • 1.44 if BMI increased 8 points during age 20-27 y/o. 

• possible that environmental factors have the most impact during growth than after growth.

Meng et al. (2017) → Population Changes in China Study

• age at menarches measured for girls born 1973-2004.

• 3,199 girls aged 6-18 in 1991-2011.

Meng et al. (2017) → Factors Predicting Early Menarche

• later born (2nd, 3rd, …child) → manifestation of urbanization increasing.

• high BMI → predicted based on role of fat triggering hypothalamus activity.

• high carbohydrate intake predicted later menarche.

• SES, household income, parental education, fat intake, exercise → did not correlate to early or late.

Girls in rural areas are having first menarches…

• older than in urban settings.

Environmental Factors Disrupting Menarche

• synthetic chemicals in environment that could impact endocrine system and reproductive health.

  • may mimic hormones, disrupt hormone synthesis or breakdown, alter development of hormone receptors, act as hormone antagonist (works against hormone), or alter hormone binding (chemical binds instead).

• sources include:

  • pesticides, plastics, electronic wastes, flame-retardants, metals, food additives, personal care products…

    • so everything.

Kumar et al. (2020) → Plastic Production

• correlation between increasing rates of global plastic production, global obesity, and global diabetic prevalence. 

Early onset of puberty has been shown to coincide with…

• increased environmental pollutants.

  • possible that exogenous chemicals that impact steroid receptors, triggering early start to puberty.

Puberty Rituals → Girls

• to celebrate the start of puberty.

• menarche is usually celebrated.

  • taboo in some cultures → associated with restricting women’s behaviours

  • ambivalent in others → don’t really acknowledge it.

Puberty Rituals → Boys

• typically associated with a certain age.

• involves rituals displaying strength, courage, and endurance.

• many cultures used pain as initiation into adulthood → prepared them for life’s challenges as an adult.

  • e.g., Samoan tattooing.

Osekihan

• red bean rice.

• cooked for celebratory meals in Japan.

• historically cooked when daughter experienced menarche.

  • not as common today.

Parent-Adolescent Relationships

• become cooler when pubertal changes become evident.

• in some cultures adolescents grow closer, especially to moms.

Touching & Talking Study

• steady increase of talking for both girls and boys until puberty…

  • daughter’s maintain.

  • son’s talk less.

• decrease in touching (hugs, etc.) from childhood through adolescents for both girls and boys.