I. Dopamine abnormalities A. Excess dopamine levels in the brain B. Dysregulation of dopamine receptors C. Dysfunction in dopamine transporters
II. Serotonin abnormalities A. Low levels of serotonin in the brain B. Imbalance in serotonin receptors C. Impaired serotonin synthesis and metabolism
III. Glutamate abnormalities A. Dysregulation of glutamate receptors B. Excessive glutamate release in the brain C. Dysfunction in glutamate transporters
IV. GABA abnormalities A. Reduced GABA levels in the brain B. Imbalance in GABA receptors C. Impaired GABAergic neurotransmission