ADHD and Addiction

Question 1

• Attention-deficit/hyperactivity disorder (ADHD) DSM-IV diagnosis

Answer 1

• Attention-deficit/hyperactivity disorder (ADHD) DSM-IV diagnosis = 6/9 inattention symptoms, and 6/9 hyperactivity/impulsivity symptoms 6 for months.

Question 2

ADHD affects how many kids?

Answer 2

• ≈ 8% of kids.

* ≈ > 2 * more likely in boys.

Question 3

what did • Jensen et al. (2001) do

Answer 3

found ADHD is comorbid with aggression, conduct disorder, oppositional defiant disorder (ODD), depression and anxiety, and tics.

Question 4

in ADHD, concordence rates are higher for ….

Answer 4

concordence rates are higher for MZ than DZ twins indicating genetic component

Question 5

what is Functional impulsivity

Answer 5

Risk taking may be selected by evolution

Question 6

what did Dickman 1990 do

Answer 6

created a funcitonal impulsivity questionnaire

Question 7

medication for ADHD

Answer 7

Medication – Methylphenidate (trade name e.g. Ritalin)

Question 8

how does Methylphenidate (trade name e.g. Ritalin) work

Answer 8

• Methylphenidate blocks the dopamine and noradrenalin reuptake transporter increasing dopamine in the synaptic cleft
• Amphetamine and cocaine do the same.

Question 9

• Childhood ADHD = reduced activation of the ????? and ?????

Answer 9

• Childhood ADHD = reduced activation of the ventral attentional stream (‘what’)(hierarchically organised), and frontoparietal cortex (executive control/working memory).

Question 10

• High risk children of addicted parents had …

Answer 10

• High risk children of addicted parents had higher anxiety, depression and ‘dysregulation’ (ADHD symptoms + cognitive impairment) at both age points.

Question 11

what did Tarter 2003 do

Answer 11

• Combined affective+dysregulation score at age 10-12 (black bars) prospectively predicted an earlier age of initiating drug use reported at age 16.
• Early onset drug use is a risk factor for adult addiction.
• Higher depression and anxiety at age 10
• Predicted early onset of drug use

Question 12

what did Wise et al 2002 do

Answer 12

• Drug hijack brain reward mechanisms.
• Electrical self-stimulation of the mesolimbic dopamine pathway creates ‘addictive’ like behaviour
• Electrode in rats head.
• Rats quickly acquire the response.
• Shows binge ‘consumption’.
• Displaces food till starvation.
• Continues despite painful foot shock.

Question 13

what did Talwar et al. 2002 do

Answer 13

Rewarding rats with mesolimbic dopamine pathway stimulation for moving in a particular direction in response to virtual whisker stimulation, achieves an incredible level of control over the rats’ movement.

Question 14

what did Kolb & Himmelsbach find

Answer 14

• Reduction of aversive states by the drug reinforces continued drug use.
• Think of pain killers. Drugs are addictive because they remove either withdrawal symptoms or psychological distress stemming from comorbid psychiatric illness.

Question 15

• Methamphetamine abusers show loss of ……………………..at 1 month abstinence

Answer 15

• Methamphetamine abusers show loss of striatal dopamine activity (in PET) at 1 month abstinence

Question 16

examples of addiciton being comorbid

Answer 16

• 36% of people with alcoholism and 53% of people with drug dependence have a mental health diagnosis, which is 2.3 and 4.5 times higher than the non-dependent population (OR).

Question 17

what did Grupe et al. (2013) do

Answer 17

• Posterior insula cortex is the primary sensory cortex for interoceptive pain, temperature, touch, itch, taste and visceral changes (aka. gustatory cortex).
• Central insula integrates emotional information from the amygdala.
• Anterior insula integrated emotional/decision information from the PFC.
• May carry information about adverse internal and emotional states which promote drug use.

Question 18

what was Naqvi’s study

Answer 18

• Naqvi et al (2007) studied stroke patients who did and didn’t have an insula damage (coloured sections = region damage).
• Strokes that damage the insula are associated with very easy quitting of smoking.

• Of 69 patients, 37 did not quit, and 32 quit.
• Of the 32 quitters 16 struggled, and 16 quit easily (‘disruption group’).
• ‘Dysruption’ group reported:
1. Quitting less than 1 day after stroke.
2. Did not start smoking again after quit.
3. Difficulty of quitting less than three on seven point scale.
4. Reported feeling no urges to smoke since quitting.
There were a disproportionate number of ‘disrupted’ smokers in the insula group (12 vs. 4), suggesting easy quitting.

Question 19

what was Naqvi’s results

Answer 19

Statistics bore this out. The insula stroke damage was the only region that was associated with disruption of addiction (easy quitting of smoking).
According to negative reinforcement theory, damage to the insula blocks experience of the negative emotional states that trigger smoking (withdrawal, depression, anxiety, fatigue etc.), making it easy to quit.