DSM Criteria
A. 6 or more symptoms of inattention
-> disruptive and developmentally inappropriate
B. 6 or more symptoms of hyperactive-impulsivity for at least 6 months and disruptive and developmentally inappropriate
C. Symptoms present before age 7-12
D. impairment from symptoms present in two or more settings
ADHD Definition
Deficits in patience and concentration + impulsive, driven and disorganized behaviors
- subtypes
- onset age before 7-12
- often difficulty in school and relationships
ADHD subtypes
- Predominantly inattentive type
- Predominantly hyperactive-impulsive type
- Combined Type
Predominantly inattentive type
- if six or more symptoms of inattention are present but <6 or hyperactive impulsivity
- sluggish tempo might also be important component (slow retrieval from memory and slow processing)
Predominantly hyperactive-impulsive type
-diagnosed if 6 or more symptoms of hyperactivity-impulsivity but less than 6 of inattention
Combined Type
-diagnosed if six or more symptoms of inattention and six or more symptoms of hyperactivity-impulsivity present
Prevalence
5% of children develop ADHD
- > 20-25% of ADHD patients have severe learning disability
- > boys 3x more likely to develop it
Long-Term Outcomes
- symptoms persists into young adulthood in 75% of cases
- increased risk for: Antisocial PD, substance abuse, mood and anxiety disorders, marital problems, traffic accidents, frequent job changes
- > often: lifelong difficulties in school, work and social relationships
Biological Factors
- PFC smaller in children with ADHD
- > regulates attention, organizing, and planning
- > abnormal activity when attempting to inhibit processes
- Immaturity hypothesis
- abnormal catecholamine neurotransmitter function (dopamine, serotonin, norepinephrine)
- Heritability
Immaturity Hypothesis
Proposes: children with ADHD neurologically immature
- brains slower to develop than normal
- > inability to maintain attention and behavioral control at appropritate level for age
Heritability
Siblings of children with ADHD: 3-4x more likely to develop it
- genetic factors implicated in twin studies
- 76% heritablity
- dopamine transporter genes might be abnormal
Psychological & Social Factors
- ADHD children more likely to belong to families experiencing frequent disruptions
- e.g. father more likely to be antisocial/criminal,
Treatments
Stimulants
Antidepressants
Behavioral Therapies
Stimulant treatment
e. g. Ritalin, Dexedrine, Aderall
- 70-85% respond with decreases in demanding, disruptive, and noncompliant behavior
- increases in mood, goal-directedness, social interactions
- increase dopamine levels in brain: enhance release and inhibit reuptake
- side effects (reduced appetite, insomnia etc.)
Antidepressants
- often prescribed when both ADHD and depression present
- positive effects on cognitive performance
- not as effective as stimulants
- symptoms often return upon discontinuation
Behavioral Thepries
Focus on reinforcement of attentive, goal-directed, and prosocial behaviors
- extinguishing of impulsive and hyperactive behaviors
- engage teachers and parents to change rewards and punishments
- > highly effective in symptom reduction
Most effective ADHD treatment
Studies suggest combination of drug treatment (e.g. ritalin) and behavioral therapy as most effective
Article: Klingberg et al. Association between Working Memory and ADHD
Working Memory training of children with ADHD led to reduction in symptoms of inattention and hyperactivity-impulsivity
- > imrpovement of response inhibition and reasoning
- > suggests association between WM and reasoning ability
Article: Prins et al. : computerized WM training with game elements
CAI: computerized assisted instruction programs
- gaming format: includes storyline, frequent and immediate feedback, multiple sensory modalities
- > Results: WM training with game elements improved: motivation, training performance, and working memory
Article: Sonuga-Barke: dual pathway model of behavior and cognition
Dual Pathway Model:
- ADHD as outcome of two pathway impairments
1. poor inhibitory control: dysregulation of thought and action pathway (DTAP)
2. poor delay aversion: Motivational Style pathway (MSP) - > ADHD symptoms: behavioral dysregulation (1)
- > poor task engagement: cognitive dysregulation (2)
Computerized assisted instruction (CAI) programs
- clear goals and objectives
- highlighting of important mateiral
- immediate feedback regarding resposne accuracy
Inhibitory Control Neural correlate
Associated with meso-cortical branch of the dopamine system projecting in cortical control centers (e.g. PFC)
-> in ADHD: DTAP causes behavioral symptoms and poor quality task engagement
Delay Aversion Neural Correlates
Linked to meso-limbic dopamine branch associated with reward circuits (nucleus accumbens)
- > alterations in reward mechanisms and characteristics of child’s early environment
- > MSP impairment
DTAP ADHD
- poor inhibitory control
- context independent
- severe and generalized cognitive dysregulation
- categorical
- less associated with genetic factors
