What does ADHD stand for? What is it?
- attention-deficit hyperactivity disorder
- developmental neuropsychiatric disorder
What are the two “symptoms” of ADHD?
- impairment of growth/development (childhood onset and temporal contiguity)
- neurological abnormality resulting in impaired ability to function (anatomically based)
What are the three subtypes of ADHD?
- ADHD predominantly inattentive
- ADHD predominately hyperactive/impulsive
- ADHD combined
What characterizes ADHD predominately inattentive?
- distracted, disorganized, forgetful, poor concentration, daydreaming
- vigilant concentration
What characterizes ADHD predominantly hyperactive/impulsive?
- fidgety, restlessness, hyperactivity, difficulty waiting and remaining seated, immature behaviours
- motor and behaviour inhibition: cognitive alertness
What does hyperactivity mean?
- refers to brain function not behavioural description
What is vigilant concentration?
- staying on task
- monitoring rules, updating the system, response execution
What areas of the brain are involved in vigilant concentration?
- reticular activating system: locus coeruleus and basal forebrain
What neurotransmitter is involved in vigilant concentration?
- norepinephrine
- continuous excessive mental work-loads
- less nt = less perseverance
- lack of “reward dependence”
What is cognitive alertness?
- orienting (noticing)
- detection: monitoring, reaction
- sensory awareness (inability to ignore stimuli)
What brain areas are involved in cognitive alertness?
- mesolimbic/mesocortical pathway
What neurotransmitter is involved in cognitive alertness?
- dopamine
- gives motivational significance to stimuli associated with reward
What is hyperfocus?
- intensive concentration on interesting and non-routine activities accompanied by temporarily diminished perception of the environment
Where is hyperfocus seen and what neurotransmitter is involved?
- facet of adult ADHD
- depleted serotonin
What is methylphenidate?
- ritalin
- phenethylamine
- reuptake inhibitor of dopamine and norepinephrine
- more potent than cocaine so more dopamine available
Why does methylphenidate have less abuse potential despite being more potent than cocaine?
- enters the brain more slowly
- no euphoria
What were the methods for the study by Liddle et al. (2001) looking at methylphenidate and ADHD?
- Go-Nogo task (75%/25%)
- continuous response task intermittent inhibition
- dynamic adjusting accuracy and rt (mistakes slow down presentation, answers speed up)
What were the results of the study conducted by Liddel et al. (2001) on methylphenidate and ADHD?
- no difference in reaction time between groups
- no difference in accuracy between ADHD+M group and TD group
- ADHD - M had more false alarms and misses (delayed processing mechanism)
What are (dextro)amphetamines?
- dex: right turning
- dexedrine and adderall
- dexedrine financed by US air force for sustained flight
What was given to pilots for sustained flight?
- “go pills”
- “no go pills”: to ensure rest (benzo, nonbenzo)
What effects result from dextroamphetamines being right-rotating?
- psychostimulnt without vasoconstriction in body
- (body predominantly let-rotating)
What causes a decline in popularity of dextroamphetamines?
- psyhoactive
- caused incidents
Why was adderall able to be patented?
- because of the blend of salts (75% dex, 25% levo)
- shire pharmaceutical
On a cellular level, how do dextroamphetamines work?
- agonists
- dopamine transporter reversed (dumps out dopamine)
- leaky vesicles
- norepinephrine and dopamine
