ADDICTION

What is addiction?

A disorder in which an individual takes a substance or enageges in behaviour that is pleasurable but eventually becomes compulsive with harmful consequences.

START

What can you become addicted to?

- work- internet - solvents - shopping

- alcohol - drugs - smoking - gambling

What are the risk factors for developing an addiction?

• Family influences
• Peers
• Stress
• Antisocial personality disorder
• D4 dopamine receptors (more sensitive to rewarding effects)
• >50% heritablity

Nicotine on the brain

Smoking - The desensitisation hypothesis

BUT the receptor shuts down temporairly immediately after.

Acetylcholine binds to neurons so they can release dopamine.

These receptors are located on the ventral tegmental area.

Nicotine molecules can also bind to a receptor on these neurons (nicotinic acetylcholine receptor)

The dopamine can only go to the nucleus accumbens which is associated with reward and pleasure.

The binding of nicotine to nAChR also transmits dopamine.

Desensitisation: closure and unresponsiveness of the receptor - the symptoms of craving/withdrawal begin when desensitized nAChR become responsive during periods of abstinence.

Alcohol typically inhibits the Corticotropin-releasing factor

Why is it so hard to quit?

Withdrawl symtptoms:- irritability - restlessness and poor concentration - depression - anxiety and stress - positive and negative reinforcement

Classical conditioning:- cues associated with smoking - 'secondary reinforcers' ('catch' in the throat, smoking itself)

Neuroadaptation

- Number of binding sites on the nicotinic cholinergic receptors in the brain increases.- This is a response to desensitization of receptors.

What happens when you quit smoking?

• Levels of corticotrophin-releasing factor increase.
• Underactivity of dopaminergic system.

Prochaska's model of change

Help available:

- CBT.- Covert sensitation (classical conditioning). - Nictotine replacement therapy. - Residential rehab.

The brain's plasticity

After 14 months of abstinence, the dopamine transporter levels (DAT) in the reward region of the brain return to nearly normal function .

References

Benowitz, N (2010) Nicotine Addiction, PMC free article.

Dawkins, L (2013) Why is it so hard to quit smoking?, The psychologist

Volcow, N (2001) Loss of Dopamine Transporters in Methamphetamine Abusers Recovers with Protracted Abstinence, The Journal of Neuroscience

THANKS!

Questions?