Copyright © 2008 The McGraw-Hill Companies, Inc. All rights reserved. 1 Adolescence 8th edition By Laurence Steinberg, Ph.D. Chapter One: Biological Transitions Insert Photo from DAL

Copyright © 2008 The McGraw-Hill Companies, Inc. All rights reserved. 2 Chapter 1 Overview  What is puberty?  What is the endocrine system?  What triggers puberty?  What are the physical changes of puberty?  Variations in the timing and tempo of puberty  What is the psychosocial impact of puberty?  Early vs. Late maturation  Eating disorders  Physical health in adolescence

Copyright © 2008 The McGraw-Hill Companies, Inc. All rights reserved. 3 Puberty: An Introduction  From Latin word pubertas (adult)  Period of lifespan in which an individual becomes capable of sexual reproduction  Hormones regulated by the endocrine system lead to physical changes  No new hormones are produced and no new bodily systems develop at puberty

Copyright © 2008 The McGraw-Hill Companies, Inc. All rights reserved. 4 The Endocrine System  Produces, circulates, and regulates hormone levels in the body  Hormones  Substances secreted by endocrine glands  Glands  Organs that stimulate particular parts of the body to respond in specific ways  Feedback loop (HPG axis)  Set point (Example: thermostat)

Copyright © 2008 The McGraw-Hill Companies, Inc. All rights reserved. 5 The Endocrine System: HPG Feedback Loop  HPG Axis:  Hypothalamus  Pituitary gland (master gland)  Gonads (testes and ovaries)  Gonads release sex hormones into bloodstream  Androgens and estrogens

Copyright © 2008 The McGraw-Hill Companies, Inc. All rights reserved. 6 What Triggers Puberty? What Triggers Puberty?  Although no new hormones in adolescence, something signals the HPG axis to kick on  Presence of mature sexual partners  Nutritional resources  Leptin may be the most important signal  Protein produced by fat cells  Must accumulate enough body fat (~11%)  Rising levels of leptin signal hypothalamus to stop inhibiting puberty (at least in females)  Adrenarche  Maturation of adrenal glands leads to physical (somatic) changes

Copyright © 2008 The McGraw-Hill Companies, Inc. All rights reserved. 7 What Role Do Hormones Play?  Organizing Role  Prenatal hormones “program” the brain to be masculine or feminine (like setting an alarm clock)  Patterns of behavior as a result of this organization may not appear until adolescence (Ex: sex differences in aggression)  Activating Role  Increase in certain hormones at puberty activates physical changes (Ex: secondary sex characteristics)

Copyright © 2008 The McGraw-Hill Companies, Inc. All rights reserved. 8 Puberty is Affected by Context  Timing of physical changes in adolescence varies by  Regions of the world  Socioeconomic class  Ethnic group  Historical era  Example: Menarche (first menstruation)  U.S. average 12 to 13 years  Lumi (New Guinea) average > 18 years Insert picture from DAL

Copyright © 2008 The McGraw-Hill Companies, Inc. All rights reserved. 9 What Are The 5 Major Physical Changes of Puberty?  Adolescent growth spurt  Development of primary sex characteristics (gonads)  Development of secondary sex characteristics (breasts, pubic hair)  Changes in body composition  Changes in circulation and respiration

Copyright © 2008 The McGraw-Hill Companies, Inc. All rights reserved. 10 Physical Changes of Puberty: Adolescent Growth Spurt  Adolescent growth spurt  Rapid acceleration in growth (height and weight)  Simultaneous release of growth hormones, thyroid hormones, and androgens  Peak Height Velocity (Time that adolescent is growing most quickly)  Average female growth spurt is 2 years earlier than the average male growth spurt

Copyright © 2008 The McGraw-Hill Companies, Inc. All rights reserved. 11 Physical Changes of Puberty: Adolescent Growth Spurt

Copyright © 2008 The McGraw-Hill Companies, Inc. All rights reserved. 12 What Are The Physical Changes of Puberty?  Changes in body composition  Relative proportions of body fat/muscle change  Different for boys (more muscle) and girls (more fat)  Skeletal changes (Bones become harder, denser, more brittle)  Closing of ends of long bones (epiphysis)  Asymmetry of growth  Circulatory and respiratory changes  Size and capacity of heart and lungs  Exercise tolerance

Copyright © 2008 The McGraw-Hill Companies, Inc. All rights reserved. 13 Sexual Maturation: Overview  Development of secondary sex characteristics  Measured in boys and girls by Tanner Stages  Changes include  growth of pubic hair  changes in appearance of sex organs  breast development

Copyright © 2008 The McGraw-Hill Companies, Inc. All rights reserved. 14 Sexual Maturation: Boys  Spermarche typically occurs 1 year after accelerated penis growth  Boys capable of fathering a child before they look like adults; opposite true for girls

Copyright © 2008 The McGraw-Hill Companies, Inc. All rights reserved. 15 Sexual Maturation: Girls  Sequence less regular than in boys  Menarche typically occurs after other secondary sex characteristics; regular ovulation follows 2 years later  Thus, girls appear physically mature before they are actually capable of reproduction

Copyright © 2008 The McGraw-Hill Companies, Inc. All rights reserved. 16 Variations in the Timing and Tempo of Puberty  No specific average age at onset or duration of puberty  No relation between the age at which puberty begins and the rate of pubertal development  Timing (early or late) and adult stature  Small effect: late maturers slightly taller as adults, early maturing girls slightly heavier as adults  Childhood height and weight  Stronger correlation with adult height and weight

Copyright © 2008 The McGraw-Hill Companies, Inc. All rights reserved. 17 Variations in the Timing and Tempo of Puberty

Copyright © 2008 The McGraw-Hill Companies, Inc. All rights reserved. 18 Individual Differences in Pubertal Maturation  Pubertal maturation  Interaction between genes and environment  Differences in timing/rate among individuals in the same general environment result chiefly from genetic factors  Two key environmental influences  Nutrition  Health  Exposure to pheromones Insert photo from DAL

Copyright © 2008 The McGraw-Hill Companies, Inc. All rights reserved. 19 Group Differences in Pubertal Maturation  Typically studied by comparing average age of menarche  Across countries  Age at menarche lower when not malnourished (Ex: Africa and United States)  Among SES groups within a country  Affluent girls reach menarche before disadvantaged girls  Within same populations but different eras

Copyright © 2008 The McGraw-Hill Companies, Inc. All rights reserved. 20 Group Differences in Pubertal Maturation  Secular trend (group trend within same region)  Leveling off in industrialized nations  Better sanitation, control of infectious diseases  U.S. average age of menarche has not changed in 30 years  Onset of puberty has continued to occur earlier among African-American girls in the United States

Copyright © 2008 The McGraw-Hill Companies, Inc. All rights reserved. 21 Group Differences in Pubertal Maturation  Secular trend (group trend within same region)  Leveling off in industrialized nations  Better sanitation, control of infectious diseases  U.S. average age of menarche has not changed in 30 years  Onset of puberty has continued to occur earlier among African-American girls in the United States

Copyright © 2008 The McGraw-Hill Companies, Inc. All rights reserved. 22 The biological changes of puberty can affect the adolescent’s behavior in at least three ways

Copyright © 2008 The McGraw-Hill Companies, Inc. All rights reserved. 23 How Do Researchers Study The Psychosocial Consequences of Puberty?  Groups compared at different stages of puberty  Cross-sectional study design  Longitudinal study design  Same adolescents tracked over time  Comparison of early vs. late maturers  When interested in the effects of pubertal timing on psychosocial outcomes

Copyright © 2008 The McGraw-Hill Companies, Inc. All rights reserved. 24 The Immediate Impact of Puberty  Self-esteem varies by gender and ethnicity  Adolescent moodiness  More fluctuations throughout the day than adults  Not solely due to hormones  Changes in patterns of sleep  Delayed phase preference and later melatonin secretion  Environmental influences and school start times  Family relationships  Peer relationships

Copyright © 2008 The McGraw-Hill Companies, Inc. All rights reserved. 25 The Immediate Impact of Puberty

Copyright © 2008 The McGraw-Hill Companies, Inc. All rights reserved. 26 The Psychosocial Impact of Specific Pubertal Events  Most adolescents react positively to pubertal changes  especially secondary sex characteristics  Reactions to menarche are varied  but less negative than in the past  Less known about boys’ reactions to first ejaculations Insert photo from DAL

Copyright © 2008 The McGraw-Hill Companies, Inc. All rights reserved. 27 Psychosocial Impact of Early or Late Maturation: Boys  Perception of being an early or late maturer is more important in affecting one’s feelings than the reality  Pros of early maturation  Popularity, better self-esteem  More responsible, cooperative, sociable later in adulthood  Cons of early maturation  More drug and alcohol use, precocious sexual activity, greater impact of victimization  Less creative, more humorless in later adulthood

Copyright © 2008 The McGraw-Hill Companies, Inc. All rights reserved. 28 Psychosocial Impact of Early or Late Maturation: Girls  Compared to early maturing boys, early maturing girls have more difficulties  Maturational deviance hypothesis  Developmental readiness hypothesis  Cultural and contextual factors (valuing thinner body types)  Pros of early maturation  Popularity with boys  Cons of early maturation  Heavier and shorter stature later in life  Precocious sexual activity, lowered self-image, higher rates of depression, eating disorders, anxiety

Copyright © 2008 The McGraw-Hill Companies, Inc. All rights reserved. 29 Psychosocial Impact of Early or Late Maturation: Girls

Copyright © 2008 The McGraw-Hill Companies, Inc. All rights reserved. 30 Eating Disorders  Body Dissatisfaction  Higher among early maturing girls  Puberty brings rapid increase in body fat for girls  Obesity  The most common pattern of disordered eating among adolescents  Basal Metabolism Rate  Disordered eating  Patterns of eating, attitudes, and behaviors that are unhealthy.

Copyright © 2008 The McGraw-Hill Companies, Inc. All rights reserved. 31 Eating Disorders  Deviation from the “ideal” physique can lead to loss of self- esteem and other problems in the adolescent’s self-image  Studies of magazines, 1970 to 1990  Ideal body shape became slimmer  Ideal body shape became less curvaceous

Copyright © 2008 The McGraw-Hill Companies, Inc. All rights reserved. 32 Marilyn Monroe Height: 5 feet 5 1/2 inches Weight: Varied, approx. 120 lbs. Measurements: Dress size: 12 Pant Size: 8 Kate Moss Height: 5 feet 6 inches Weight: 105 lbs. Measurements: Dress size: 4 Pant Size: 2

Copyright © 2008 The McGraw-Hill Companies, Inc. All rights reserved. 33 Eating Disorders  Characterized by:  severe disturbance in eating behavior  Intense fear of becoming overweight which leads to the pursuit of thinness  This fear is relentless and may become deadly  Types of Adult Eating Disorders:  Anorexia Nervosa  Bulimia Nervosa  Obesity also has disordered eating patterns, but at this moment it is not considered an eating disorder

Copyright © 2008 The McGraw-Hill Companies, Inc. All rights reserved. 34 Eating Disorders: Bulimia & Anorexia Nervosa  Adolescents with these eating disorders have an extremely distorted body image  The definitions below are provided by the book, but I do not agree…I am providing them as a point of reference:  Bulimia  Eating binges; force themselves to vomit to avoid weight gain  3% of adolescents are genuine bulimics  Anorexia  Starve themselves to keep weight down  Fewer than one-half of 1% of adolescents  Bulimia and Anorexia 10 times more common among females

Copyright © 2008 The McGraw-Hill Companies, Inc. All rights reserved. 35 Anorexia Nervosa  Name originated from the idea that there was a “lack of appetite induced by nervousness”  Characterized by:  Intense fear of weight gain  Refusal to maintain healthy body weight  Women:  At this time, this diagnosis requires that a woman does not have their period. However, there is much controversy associated with this.  Men:  Decrease in sexual appetite and testosterone  Patients may deny having a problem  May be quietly proud of their achieved thinness  May be life persistent  Mortality rate is 12 times higher than regular population  Death is usually due to physiological consequences (i.e. brain atrophy, etc. ) or suicide

Copyright © 2008 The McGraw-Hill Companies, Inc. All rights reserved. 36 Types of Anorexia Nervosa  Restricting Type:  Limit food and caloric intake  Avoid eating in front of others  When eating with others they may eat slowly or dispose of food  Admired by others with eating disorders  Binge Eating/Purging Type:  Either binge, purge, or binge and purge  Binge: out of control eating of amounts of food that are far greater than what a normal person would eat  May be followed by purging  Purging: Self induced vomiting, misuse of laxatives, diuretics, enemas, etc  This doesn’t stop caloric intake  Approximately 30% to 50% go from Restricting to Binge Eating Purging

Copyright © 2008 The McGraw-Hill Companies, Inc. All rights reserved. 37 Bulimia Nervosa  Characterized by:  Binge eating and efforts to prevent weight gain by using unhealthy behaviors such as self induced vomiting, laxatives, exercise, etc.  Person is not severely underweight. Typically, they are normal weight.  Usually begins by restricting eating to lose weight. Then the person eats “forbidden food”.  Binge: may be equal to about 4,800 calories  May feel disgusted, but continue due to fear of weight gain  Feel shame and guilt

Copyright © 2008 The McGraw-Hill Companies, Inc. All rights reserved. 38 Types of Bulimia Nervosa  Purging:  Vomiting, laxatives, diuretics  Most common (make up 80% of those diagnosed with Bulimia Nervosa).  Non Purging:  Exercise

Copyright © 2008 The McGraw-Hill Companies, Inc. All rights reserved. 39 Risk Factors for Eating Disorders  Eating Disorders are believed to be caused by an interaction of biological, socio cultural, family, and individual variables.

Copyright © 2008 The McGraw-Hill Companies, Inc. All rights reserved. 40 Treatment for Anorexia Nervosa  Medications:  No strong evidence that medication is helpful  Antidepressants and antipsychotic medications are sometimes used to help with disturbed thinking  Family Therapy:  Treatment of choice for adolescents  Therapist works with parents to get child to begin to eat again  After weight gain, other family problems are discussed  Randomized controlled trials show that patients who receive family therapy do better than the control group and five years after treatment 75 to 90 percent are fully recovered  Cognitive Behavioral Therapy:  Changing behavior and maladaptive ways of thinking  Treatment will usually last for one to two years  Modifying distorted beliefs about food, weight, and the self which have led to the disorder  Recovery rate of about 17%

Copyright © 2008 The McGraw-Hill Companies, Inc. All rights reserved. 41 Treatment for Bulimia Nervosa  Medication:  Antidepressants are commonly used  co-morbidity with mood disorders may be a factor  Seem to decrease binges and improve patient’s mood and preoccupation with shape and weight  Cognitive Behavioral Therapy:  Treatment of choice  Shown to be superior to medication and interpersonal therapy  Combining CBT with medication only slightly increases the results  Used to normalize eating patterns  Meal planning, nutritional education, and ending binging and purging cycles by teaching the person to eat small amounts of food throughout the day  Changing cognitions and behaviors that initiate binge cycle through challenging dysfunctional thought patterns such as:  All or nothing thinking  Idea of good food versus bad food

Copyright © 2008 The McGraw-Hill Companies, Inc. All rights reserved. 42 Treatment Outcomes  Eating Disorders are difficult to treat & have high relapse rates  Anorexia Nervosa:  Study conducted by Lowe two years after treatment:  16% no longer alive (mostly due to complications of starvation or suicide)  10% had not recovered  21% partially recovered  51% completely recovered  Bulimia Nervosa:  Study conducted 11 years after treatment:  0.5% mortality rate  70% recovered  30% still had it  It is important to note that the client may recover, but may still have food issues.

Copyright © 2008 The McGraw-Hill Companies, Inc. All rights reserved. 43 Physical Health and Health Care in Adolescence Physical Health and Health Care in Adolescence  Adolescent health care needs differ from those of children and adults  Health compromising and health enhancing behaviors  School-based health centers  10% are family planning visits  Most visits involve injuries, acute illnesses and mental health Insert photo from DAL

Copyright © 2008 The McGraw-Hill Companies, Inc. All rights reserved. 44 Physical Health and Health Care in Adolescence Physical Health and Health Care in Adolescence  PARADOX: Adolescence is a healthy period of the lifespan  But nearly 1 in 15 adolescents experiences at least one disabling chronic illness:  mental disorders (depression)  respiratory illnesses (asthma)  muscular and skeletal disorders (arthritis)  muscular and skeletal disorders (arthritis)  Threats to health have psychosocial causes (not natural causes)

Copyright © 2008 The McGraw-Hill Companies, Inc. All rights reserved. 45 Adolescent Mortality  Today  45% of teen deaths due to car accidents and other unintentional injuries  30% of teen deaths due to homicide and suicide  50 Years Ago  Most deaths from illness and disease