Substance Use Disorder, Neurobiology of SUDs, SUD Statistics

Appropriate Drug Use

Using them without consequences

Drug Misuse

Use in a manner that may lead to significant consequences across all life areas

Drug Abuse

Life consequences: self-moderating successful or more significant problem in an early stage

Drug Addiction

Moderation is not effective. The condition leads to death without intervention

Components of Addiction

• Tolerance: Pharmacokinetic tolerance (drug not reaching the brain’s receptors), Pharmacodynamic tolerance (receptors are damaged or lost)

• Dependence: When the body changes to adapt to the constant access and use of the drug

• Addiction: Addiction is defined by behavior. The substance abuse will continue despite negative consequences

Prevalent Substance Use Disorders

• Alcohol: most common SUD in adults

• Tobacco/Nicotine: Leading cause of preventable death

• Opioid: Rising prevalence

• Cannabis: Legalization trends

• Stimulant: Cocaine, meth

Overdose Trends

• Opioids: Dominate overdose deaths

• Polysubstance use: greatly increases mortality risk

Stimulants and Neurotransmitters

Effects dopamine, norepinephrine

• Euphoria and increased alertness

Depressants and Neurotransmitters

Affects GABA (calming neurotransmitter)

Analgesics and Neurotransmitters

Affects Enkephalins and Endorphins

Hallucinogens and Neurotransmitters

Affects serotonin, glutamate, and endocannabinoids

Different Neurotransmitters

GABA: Inhibitory (Stabilizes Glutamate)

Glutamate: Excitatory (Stabilizes GABA)

Serotonin: Involved in regulating mood, sleep, eating, arousal, and pain

Dopamine: pleasure, reward, motivation

Physiological effects of Alcohol

CNS Depressant (Sedation, impaired motor/cognitive function)

• Suppress the action of GABA neurons and others that inhibit dopamine release

Physiological effects of Opioids

CNS Depressant (euphoria, respiratory depression)

Alcohol and Opioids Together

Both act to slow the brainstem to slow breathing, but they act through different mechanisms

• Alcohol decreases excitatory signals and increases inhibitory signals

• Opioids add to the effect by making neurons less responsive to excitatory signals

Mesolimbic Dopamine System (Midbrain)

Prime target of addictive drugs

• Role: Mediates reward, motivation, reinforcement

• Addictive Substances: Hijack system → excessive dopamine → compulsive drug-seeking behavior

Ventral Tegmental Area, at top of brainstem, projects to areas of brain

Prefrontal Cortex and Addiction

• Executive Function

• Regulates emotion and behavior

• Involved in judgment and morality

• Critical for attention and focus

Societal Factors

Stigma → reduces help-seeking

Access to healthcare, treatment programs, harm reduction services

Psychological Factors

Co-occurring mental health disorders

Trauma history or adverse childhood experiences

SAMHSA Data

• Alcohol remains the most widely used substance, but opioid-related issues cause the highest mortality and marijuana is second

• 17.1% of people aged 12 or older had a SUD in the past year

• SUD are developed in adolescence (easier to get treatment here)