What Is Drug Dependency?

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• Chronic, often relapsing condition

• Compulsive drug seeking and use, despite harmful consequences

• Difficulty resisting impulses to use, due to brain impacts over longterm use

 

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What Happens to Your Brain When You Take Drugs?

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• Chemicals in drugs tap into the brain’s communication system

• These chemicals disrupt the way nerve cells normally send, receive, and process information

• 2 ways to disrupt:

(1) Imitating the brain’s natural chemical messengers 

(2) Overstimulating the “reward circuit” of the brain

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How Different Drugs Affect Brain

 

 

Marijuana & Heroin

 

•  Similar structure to chemical messengers (neurotransmitters)naturally produced by brain

•  “Fool” the brain’s receptors & activate nerve cells to send abnormal messages

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Cocaine or Methamphetamine

 

• Cause nerve cells to release abnormally large amounts of natural neurotransmitters (mainly dopamine)

• Stop the normal recycling of these brain chemicals needed to shut off the signalilng between neurons

• Brain flooded with dopamine

• Dopamine is present in brain regions that control movement, emotion, motivation, and feelings of pleasure

• Overstimulation of reward system, that usually responds to natural behaviours linked to survival (eating, spending time with loved ones, etc.) produces euphoric effects in response to drug

• Reaction sets up reinforcing pattern that “teaches” people to repeat the rewarding behaviour of abusing drugs​

• After long term use, brain adapts to flooding of dopamine by producing less dopamine or reducing the number of dopamine receptors in the reward circuit

• Leads to less impact from dopamine on reward circuit

• Abuser experiences less affect from drug & less enjoyment in other events that used to bring pleasure

• Addicted person keeps using to bring dopamine function back to normal

• Addicted person needs more of drug to get same effect (tolerance)

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​​​Other impacts from long-term drug use

 

• Glutamate is a neurotransmitter that influences the reward circuit & ability to learn

• When optimal concentration of glutamate is affected by drug abuse, the brain compensates = , cognitive impairment

• Brain imaging studies show changes in areas of the brain critical to judgment, decision making, learning & memory & behaviour control

• These changes lead abuser to seek out & take drugs compulsively despite negative consequences

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Why Do Some People Get Addicted While Other People Don't?

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Risk for addiction influenced by:

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• Biology

• Social environment

• Age or stage of development.

• The more risk factors a person has, the greater the chance taking drugs will lead to addiction

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Biology

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• Genes that people are born with & environmental influences = 1/2 addiction vulnerability

• Gender, ethnicity & presence of other mental disorders 

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Environment

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• Family and friends

• Socioeconomic status

• Quality of life in general

• Peer pressure

• Physical & sexual abuse

• Stress

• Quality of parenting 

 

Development

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• Genetic and environmental factors interact with critical developmental stages in a person’s life

• Earlier that drug use begins, the more likely it will progress to more serious abuse

• Adolescents vulnerable,  as areas in their brains that control decision making, judgment & self-control are still developing

• Adolescents may be therefore prone to risk-taking behaviours, such as trying drugs