Methamphetamine affects neurotransmitters like dopamine, norepinephrine, epinephrine, and serotonin by blocking their reabsorption and increasing their release, causing dangerous imbalances in the brain. It is highly addictive due to inducing feelings of euphoria by raising dopamine levels, and subsequent crashes when levels fall. Long-term use kills neurotransmitter cells, permanently altering emotions and reward processing and increasing risks of mental health issues like depression.