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Causes of Mental Causes of Mental RetardationRetardation
Genetic, environmental, and Genetic, environmental, and psychosocial causespsychosocial causes
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Key vocabularyKey vocabulary
► Perinatal causesPerinatal causes► Perinatal causesPerinatal causes► Postnatal causesPostnatal causes► Social correlatesSocial correlates► Psychological correlatesPsychological correlates► Preventative measuresPreventative measures
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Key vocabularyKey vocabulary
► Roles of genes and chromosomes in Roles of genes and chromosomes in heredityheredity
► Autosomal genetic disordersAutosomal genetic disorders► Sex linked genetic disordersSex linked genetic disorders► Disorders related to the number of Disorders related to the number of
chromosomeschromosomes► Disorders with multiple or unknown causesDisorders with multiple or unknown causes► Genetic testing and genetic counselingGenetic testing and genetic counseling
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CausesCauses
►Direct cause is more frequently Direct cause is more frequently not known than knownnot known than known
►Many persons with a label of mental Many persons with a label of mental retardation are considered to have had retardation are considered to have had the potential of developing in a typical the potential of developing in a typical sequence or ratesequence or rate
► Implication of preventableImplication of preventable►No estimate of numbersNo estimate of numbers
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Prenatal causesPrenatal causes
►Teratogens: agents causing a defect in Teratogens: agents causing a defect in a developing embryo or fetusa developing embryo or fetus InfectionsInfections RadiationRadiation Maternal nutritionMaternal nutrition Low birth weightLow birth weight Chromosomal disordersChromosomal disorders Developmental disorders of brain Developmental disorders of brain
formationformation Environmental influencesEnvironmental influences
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InfectionsInfections
►ToxoplasmosisToxoplasmosis►RubellaRubella►CytomegalovirusCytomegalovirus►Syphilis Syphilis ►HIVHIV►UTIUTI
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RadiationRadiation
►Noted with survivors of the A-bomb on Noted with survivors of the A-bomb on Hiroshima and NagasakiHiroshima and Nagasaki
►Radiation has effects depending on the Radiation has effects depending on the time of exposure and intensity (dose)time of exposure and intensity (dose)
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Maternal NutritionMaternal Nutrition
►Malnutrition may have effects both pre- Malnutrition may have effects both pre- and post-natallyand post-natally
►Major concern in developing countriesMajor concern in developing countries►Low weight gain in pregnancy has Low weight gain in pregnancy has
differential effects for different differential effects for different populationspopulations
►Low birth weight—may result in as Low birth weight—may result in as much as 40 to 60% reduction in brain much as 40 to 60% reduction in brain cellscells
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Maternal ageMaternal age
►Over 36 and under 16 at risk for low Over 36 and under 16 at risk for low birth weightbirth weight
►Younger mothers prone to giving birth Younger mothers prone to giving birth early (LBW)early (LBW)
►Reasons for mental retardation from Reasons for mental retardation from younger mothers or LBW not knownyounger mothers or LBW not known
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Lack of Pre-natal CareLack of Pre-natal Care
► Sometimes racial differentialSometimes racial differential► Increased risk of premature rupture of Increased risk of premature rupture of
amniotic membranesamniotic membranes► Maternal health problemsMaternal health problems► Drug abuse and other substance abuseDrug abuse and other substance abuse
LBWLBW FASFAS FAEFAE NicotineNicotine Other drugsOther drugs
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Maternal health problemsMaternal health problems
►Endocrine disorders; e.g., diabetesEndocrine disorders; e.g., diabetes►Cardiovascular disordersCardiovascular disorders►AnemiaAnemia►Treatments for disorders affects fetusTreatments for disorders affects fetus
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Drug and alcohol abuseDrug and alcohol abuse
►Drug use increasingDrug use increasing►Alcohol use during pregnancyAlcohol use during pregnancy
LBWLBW MicrocephalyMicrocephaly Heart defectsHeart defects Facial abnormalitiesFacial abnormalities Poor growth developmental delayPoor growth developmental delay Behavioral difficultiesBehavioral difficulties Attention problemsAttention problems
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►Nicotine useNicotine use Increased probability of miscarriageIncreased probability of miscarriage Developmental delayDevelopmental delay
►Cocaine, heroine, methadoneCocaine, heroine, methadone LBWLBW WithdrawalWithdrawal Small head circumferenceSmall head circumference Developmental delayDevelopmental delay Language problemsLanguage problems
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Perinatal causesPerinatal causes
► Anoxia and asphyxiaAnoxia and asphyxia► Prematurity- prior to 37 weeksPrematurity- prior to 37 weeks► Low birth weight –under 5 ½ poundsLow birth weight –under 5 ½ pounds► HemorrhagesHemorrhages► Metabolic problemsMetabolic problems► SeizuresSeizures► Birthing problemsBirthing problems
Multiple birthsMultiple births Abnormal presentationAbnormal presentation prolaspe of umbilical cordprolaspe of umbilical cord
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►Respiratory distress syndromeRespiratory distress syndrome lack of sulfactant (coats the alveoli)lack of sulfactant (coats the alveoli) Can result in collapsed alveoliCan result in collapsed alveoli
►JaundiceJaundice►Rh incompatibilityRh incompatibility
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Postnatal causesPostnatal causes
►Quality of attachmentQuality of attachment► IllnessesIllnesses
EncephalitisEncephalitis MeningitisMeningitis PoisoningPoisoning MalnutritionMalnutrition InjuriesInjuries
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Psychosocial factorsPsychosocial factors► Social correlatesSocial correlates
Low SESLow SES Nutrition Nutrition PovertyPoverty Family sizeFamily size Low maternal Low maternal
intelligenceintelligence Low maternal Low maternal
educational leveleducational level Absence of parentsAbsence of parents Language Language
environmentenvironment
► Psychological Psychological correlatescorrelates Child rearing practicesChild rearing practices Abuse and neglectAbuse and neglect
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1927- Buck v Bell 1927- Buck v Bell
““We have seen more than once that the We have seen more than once that the public welfare may call upon the best public welfare may call upon the best citizens citizens
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► Turner’s syndromeTurner’s syndrome► Affects femalesAffects females► Incomplete x Incomplete x
chromosomechromosome► Short statureShort stature► Webbed neckWebbed neck► Low hairline in backLow hairline in back► Skeletal deformitiesSkeletal deformities
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Fragile X SyndromeFragile X Syndrome
► Mental retardationMental retardation HyperactivityHyperactivity Short attention span Short attention span *Tactilely defensive *Tactilely defensive Hand-flapping Hand-flapping Hand-biting Hand-biting Poor eye contact Poor eye contact *Perseverative *Perseverative speechspeech Hyperextensible MP jointsHyperextensible MP joints Large or Large or prominent earsprominent ears Large testiclesLarge testicles *Simian crease or Sydney line *Simian crease or Sydney line Family history of mental retardation Family history of mental retardation
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Fragile X SyndromeFragile X Syndrome► In males, generally see a decrease in In males, generally see a decrease in
IQs over time IQs over time ►Concrete thinkingConcrete thinking►Facial features:Facial features:
Long faceLong face High arched palateHigh arched palate Long earsLong ears
► In females, less like to have a label of In females, less like to have a label of retardation; less severe featuresretardation; less severe features
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► Fragile X syndromeFragile X syndrome► Boys Boys
distractible and impulsive, with symptoms of distractible and impulsive, with symptoms of attention deficit hyperactivity disorder (ADHD) attention deficit hyperactivity disorder (ADHD)
short attention spans and difficulty staying on short attention spans and difficulty staying on task. task.
stereotypic behaviors, such as hand flapping and stereotypic behaviors, such as hand flapping and chewing on skin, clothing, or objects,chewing on skin, clothing, or objects,
Sensory processing problems may manifest Sensory processing problems may manifest themselves as tactile defensiveness, or sensory themselves as tactile defensiveness, or sensory defensiveness.defensiveness.
► Anxiety in both boys and girls manifests itself Anxiety in both boys and girls manifests itself in various waysin various ways Girls may show less hyperactivity, but still have Girls may show less hyperactivity, but still have
many symptoms of ADHD.many symptoms of ADHD.
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MicrocephalyMicrocephaly► Failure of the brain to grow at a normal rateFailure of the brain to grow at a normal rate► infections, genetic disorders, and severe infections, genetic disorders, and severe
malnutrition.malnutrition.► Primary causesPrimary causes
Down's syndromeDown's syndrome cri du chat syndromecri du chat syndrome Seckel's syndrome Seckel's syndrome Rubinstein-Taybi syndromeRubinstein-Taybi syndrome trisomy 13trisomy 13 trisomy 18trisomy 18 Smith-Lemli-Opitz syndrome Smith-Lemli-Opitz syndrome Cornelia de Lange syndrome Cornelia de Lange syndrome
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CRI DU CHAT SyndromeCRI DU CHAT Syndrome► missing a piece of chromosome number 5. missing a piece of chromosome number 5. ► high-pitched cry sounds like a cat (for which the high-pitched cry sounds like a cat (for which the
syndrome was named) syndrome was named) ► Low birth weight and slow growth Low birth weight and slow growth ► small head small head ► wide-set eyes wide-set eyes ► downward slant to the eyesdownward slant to the eyes► small jaw small jaw ► low set ears (may be malformed) low set ears (may be malformed) ► skin tags just in front of the ear skin tags just in front of the ear ► partial webbing or fusing of fingers or toes partial webbing or fusing of fingers or toes ► single line in the palm of the hand (single line in the palm of the hand (simian creasesimian crease) ) ► mental retardationmental retardation ► slow or incomplete development of motor skills slow or incomplete development of motor skills
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