| Neurotransmitter | Major functions | Associated disorders or problems |
|---|---|---|
| Dopamine | Reward, motivation, executive function (in frontal lobes), control of movements | Too little: attention-deficit/hyperactivity disorder Too much: inappropriate aggression, schizophrenia |
| Serotonin | Mood, sleep, motivation | Too little: depression and obsessive-compulsive disorder Too much: lack of motivation |
| Acetylcholine | Storing new information in memory, fight-or-flight response | Too little: delusions Too much: spasms, tremors, convulsions |
| Adrenaline (also called epinephrine) | Attention, fight-or-flight response | Too little: depression Too much: over-arousal, feelings of dread or apprehension |
| Noradrenaline (also called norepinephrine) | Attention, fight-or-flight response | Too little: distractibility, fatigue, depression Too much: anxiety disorders, schizophrenia |
| Glutamate | Registering pain, storing new information in memory | Too little: schizophrenia Too much: substance abuse |
| Gamma-amino butyric acid (GABA) | Inhibits brain activity in specific areas | Too little: anxiety, panic disorder (possibly) Too much: lack of motivation |
| Endogenous cannabinoids | Emotion, attention, memory, appetite, control of movements | Too little: chronic pain Too much: eating disorders, memory impairment, attention difficulties, schizophrenia (possibly) |
| Sources: Based on Bressan & Crippa, 2005; Buchsbaum et al., 2006; Eger et al., 2002; Giuffrida et al., 2004; Goddard et al., 2001; Kalivas & Volkow, 2005;Meana et al., 1992; Muller & Schwarz, 2006; Mundo, Richter, et al., 2000; Nemeroff, 1998; Nutt & Lawson, 1992; Rao & Lyketsos, 1998; Wilson & Nicoll, 2001. | ||