| Neurotransmitter | Primary Roles | Associated Disorder |
|---|---|---|
| Acetylcholine | Learning, memory Muscle contractions | Alzheimer’s disease |
| Dopamine | Movement Thought processes Rewarding sensations | Parkinson’s disease Schizophrenia Drug addiction |
| Serotonin | Emotional states Sleep Sensory perception | Depression |
| Norepinephrine | Physical arousal Learning, memory Regulation of sleep | Depression, stress |
| Glutamate | Excitatory messages | Seizures Alzheimer’s disease |
| GABA | Inhibitory messages | Anxiety disorders |
| Endorphins | Pain perception Positive emotions | Opioid addiction |