Centuries-old use: Societies have long sought opioids for their euphoria and pain relief.
1800s: Morphine was extracted from opium poppies and widely used during the American Civil War.
Introduction of Heroin: Developed as a “non-addictive” substitute for morphine but turned out problematic in the 20th century.
Modern Day: Prescription opioids like fentanyl and oxycodone are prevalent in America, leading to more annual deaths from overdoses than car accidents.
How Opioids Affect the Brain
Opioid Receptors: Opioids interact with receptors in the brain to stop electric pulses in neurons, which dampens pain signals.
Types of Receptors:
Mu (primary, responsible for most effects)
Kappa
Delta
Mu Receptor: Critical for slowing breathing, eliminating pain, and creating euphoria. Excessive activation leads to addiction.
Mechanism of Addiction
Midbrain Involvement: Mu-opioid receptors deactivate GABAergic neurons (off-switch for pleasure).
Dopamine Release: Inhibition of GABAergic neurons leads to a flood of dopamine in the brain’s pleasure circuits.
Areas Affected:
Nucleus accumbens (triggers happiness)
Amygdala (reduces anxiety and stress)
Consequences: Decision-making areas are compromised, leading to cravings.
Withdrawal and Dependency
Withdrawal Symptoms: Anxiety, elevated stress hormones, persistent diarrhea, hot and cold sweats, goosebumps.
Functional Addiction: Users can often maintain daily activities despite being addicted.
Physical Adaptation: Brain circuits adapt to opioids, making withdrawal extremely difficult and driving the cycle of addiction.
Increased Tolerance: Over time, more opioids are needed to achieve the same effect, linking pain with withdrawal.