The neurotransmitter and EEG connection is not very well understood as the correlation is not precise. It is important to note the effects of medication on brainwaves when conducting neurofeedback as well as when conducting baseline assessments. Neurofeedback causes fundamental shifts in neurotransmitters in the same way that drugs can be used to alter them.
Caffeine & Nicotine: Ingestion of caffeine and nicotine suppresses alpha and theta amplitude. It is also noted to increase beta and decrease slow wave, hence reducing sleepiness and increasing focus.
Marijuana: Marijuana, hashish, and THC increase frontal alpha amplitude, phase synchrony, and interhemispheric hyper coherence. Marijuana affects EEG for approximately 3 days by increasing global alpha levels (ie. states of relaxation).
Alcohol: Increased beta; and decreased thalpha (6-10 Hz) and alpha are associated with alcoholism or risk for alcoholism. Alcohol produces EEG activation in the short term and EEG slowing in the long term. Immediately after consuming an alcoholic beverage, theta and low-frequency alpha amplitudes increase.
Lithium: Lithium can increase theta and beta amplitudes, and slow the peak frequency of alpha.
Glue Solvents: The abuse of solvents like airplane glue markedly slows the alpha peak frequency as does brain trauma that produces coma.
Barbiturates: Barbiturates increase beta and sleep spindles, and slightly decrease alpha.
Antibiotics: Antibiotics can markedly increase theta amplitude.
Antihistamines: Both sedating and nonsedating antihistamines can increase theta amplitude and the theta/beta ratio.
Cocaine: Cocaine increases beta amplitude.
Narcotics: Narcotics like heroin and morphine increase alpha amplitude.