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Autistic, ADHD, Stress, and Substance Abuse Disorders

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Impairments in reciprocal social interaction. Stereotyped behaviors/interests ... NE incr in hypothalamus, frontal cortex, lateral basal forebrain. HPA hormones ... – PowerPoint PPT presentation

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Title: Autistic, ADHD, Stress, and Substance Abuse Disorders


1
Autistic, ADHD, Stress, and Substance Abuse
Disorders
2
Autism Spectrum Disorders
  • Pervasive Developmental Disorders
  • Autistic Disorder
  • Aspergers Disorder
  • Childhood Disintegrative Disorder
  • Retts Disorder
  • PDD-NOS

3
Autism Spectrum Disorders
  • Autism
  • Impairments in reciprocal social interaction
  • Stereotyped behaviors/interests
  • Impairment in communication/ language
  • Onset prior to 3
  • Behavior is disordered, not just delayed

4
Autism Spectrum Disorders
  • Possible Causes
  • Biological
  • Hereditary
  • 2-3 of siblings of ASD are autistic.
  • 70 concordance rate for MZ

5
Autism Spectrum Disorders
  • Brain Pathology
  • Increased brain weight and volume in
    preadolescent ASD
  • Normal head circumference _at_ birth ? increasing
    brain volume occurring between 2-4 yrs
  • Disproportionate increase in white matter volume
    relative to gray matter (e.g., myelin may be
    altered)
  • Limbic System small neuronal cell sizes and
    increased cell packing density (consistent with
    developmental curtailment)
  • Impaired declarative memory

6
Autism Spectrum Disorders
  • Brain Pathology

7
Autism Spectrum Disorders
  • Brain Pathology

8
ADHD
  • Attention-deficit/hyperactivity disorder (ADHD)
  • A disorder characterized by uninhibited
    responses, lack of sustained attention, and
    hyperactivity first shows itself in childhood.

9
ADHD
  • Possible Causes
  • Genetics
  • Family and Twin Studies
  • Learning
  • Steeper slope between strength of reinforcement
    delay to reinforcing stimulus

10
ADHD
  • Possible Causes
  • Biological
  • Evidence to suggest that abnormalities in
    dopaminergic transmission play a role in ADHD
  • Brain structures
  • Studies of brain structure of people with ADHD do
    not reveal any localized abnormalities, though
    the total volume of their brains is approximately
    4 smaller than normal

11
Stress Disorders
  • Stress
  • General term that can refer either to a stress
    response or to a stressor (stressful situation)
  • Stressor
  • A stimulus (or situation) that produces a stress
    response

12
Hypothalamic Pituitary Adrenal (HPA) Axis
  • SNS hormones
  • Epiglucose metabolism, incr heart output
  • NEincr in hypothalamus, frontal cortex, lateral
    basal forebrain
  • HPA hormones
  • Cortisolincr glucose metabolism, decr
    sensitivity of gonads to LH

13
Posttraumatic Stress Disorder
  • Diagnosis
  • Reexperiencing
  • Avoidance and Numbing
  • Hyperarousal
  • Risk Factors
  • Demographics (gender, age, education level)
  • Premorbid diagnoses
  • Genetics
  • Prior trauma
  • Specific aspects of the trauma

14
PTSD and Hippocampal Volume
  • MRI hippocampal volume reduced in PTSD veterans
    vs. non-PTSD vets and controls (Bremner et al.,
    1995 Gurvits et al, 1996)

15
Posttraumatic Stress Disorder
  • Alterations in HPA
  • Lower levels of cortisol ?
  • Increased and sensitivity of receptors
  • PTSD Treatment
  • Secondary interventions
  • Pharmacologic vs. psychological interventions
  • Tertiary interventions

16
Stress Disorders
  • Stress and Health
  • Long term effects of chronically elevated
    cortisol
  • Increased blood pressure
  • Muscle tissue damage
  • Steroid diabetes
  • Infertility
  • Growth stunting
  • Immune suppression
  • Brain damage

17
Substance Use/Abuse
  • Physical versus Psychological Addiction
  • Tolerance
  • increasingly large doses of drugs must be taken
    to achieve a particular effect
  • Caused by compensatory mechanisms
  • Withdrawal symptoms
  • Symptoms opposite to those produced by a drug
    when the drug is suddenly no longer taken
  • Caused by compensatory mechanisms

18
Substance Use/Abuse
  • Positive Reinforcement
  • Strengthens the response that was just made,
    namely, taking the drug
  • Drugs with the most immediate effects tend to be
    the most addictive.
  • Negative Reinforcement
  • The removal or reduction of an aversive stimulus
  • Increases the frequency of that response.

19
Substance Use/Abuse
  • Craving and Relapse
  • Reinstatement model
  • Brain mechanisms
  • Activation of mesolimbic system of DA
  • Relapse? stimuli assoc with drug involve amygdala
    mesolimbic DA system
  • Lower activity of PFC anterior cingulate in
    abstaining cocaine abusers vs normal

20
Substance Use/Abuse
  • Opiates
  • Endogenous opiates secreted during survival
    tasks? stimulate receptors that produce analgesia
    ? reduces inhibitory effects of pain

21
Substance Use/Abuse
  • Opium
  • Neural Basis of Reinforcing Effects
  • Periaqueductal gray matter (PAG) analgesia.
  • Preoptic area hypothermia (reduction of body
    temperature).
  • Mesencephalic reticular formation sedation
  • Ventral Tegmental area (VTA) and the nucleus
    accumbens reinforcing effects of opiates.

22
Substance Use/Abuse
  • Cocaine and Amphetamine
  • Cocaine amphetamine have similar behavioral
    effects, b/c both act as potent dopamine agonists
  • Cocaine binds with and deactivates DA
    transporter proteins, thus blocking DA reuptake
  • Amphetamine displaces neurotransmitter molecules
    (noradrenaline, dopamine) from storage areas
    prevents reuptake inhibits MAO

23
Substance Use/Abuse
  • Cocaine Amphetamine
  • Effects of cocaine amphetamine
  • Prior abusers of meth showed decr dopamine
    transporters in caudate nucleus putamen, even
    after 3-yr abstinence
  • Incr concentration of DA in nucleus accumbens

24
Substance Use/Abuse
  • Nicotine
  • Accounts for more deaths than the so-called hard
    drugs.
  • 1/3 of the adult population of the world smokes.
  • By 2020, tobacco will be the largest single
    health problem worldwide, with 8.4 million deaths
    per year

25
Substance Use/Abuse
  • Nicotine
  • Stimulates acetylcholine receptors
  • Incr activity of DA in the mesolimbic system
  • Injections of nicotine agonist into ventral
    tegmental area reinforces conditioned place
    preference.

26
Substance Use/Abuse
  • Alcohol and Barbiturates
  • Alcohol
  • A large percentage of deaths and injuries caused
    by motor vehicle accidents are related to alcohol

27
Substance Use/Abuse
  • Alcohol
  • Behavioral effects
  • Mild euphoria
  • Relieves anxiety
  • Brain mechanisms
  • Incr DA in mesolimbic system nucleus accumbens
  • Sites of action
  • Indirect agonist at GABAA receptors
  • Indirect antagonist at NMDA receptors
  • Stimulation of both receptors systems triggers
    apoptosis (cellular death)

28
Substance Use/Abuse
  • Cannabis
  • Brain mechanisms
  • Site of action is the endogenous cannabinoid
    receptor (CB1)
  • Stimulates release of DA in nucleus accumbens
    ventral tegmental area
  • Acts directly DA terminal buttons

29
Substance Use/Abuse
  • Cannabis
  • Brain mechanisms
  • Disrupts normal functioning of the hippocampus
  • Long-term damage
  • Bronchitis, increased risk of lung cancer, minor
    impairments of attention and memory, and slower
    decision making
  • Subtle cognitive impairments

30
Substance Use/Abuse
  • Heritability and Drug Abuse
  • Heritability Studies of Humans
  • Heritability of smoking is just as strong as that
    of alcoholism
  • Twin study alcoholism and nicotine dependence
    have genetic factors in common, which explains
    why alcoholics are often addicted to nicotine.

31
Substance Use/Abuse
  • Treatment
  • Heroin
  • Methadone
  • Cocaine
  • Cocaine immunized rats
  • Nicotine
  • Patch/gum
  • Alcohol
  • Serotonin agonists

32
Student Survey
  • 20. Overall, the instructors teaching was
  • 1. Excellent
  • 2. Very Good
  • 3. Good
  • 4. Fair
  • 5. Poor
  • Overall, this course was
  • 1. Excellent
  • 2. Very Good
  • 3. Good
  • 4. Fair
  • 5. Poor
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