Biochemical evidence suggests a role for n-3 polyunsaturated fatty acids (n-3 PUFAs) in the regulation of behavioral disturbances. A number of studies have revealed an association between reduced n-3 PUFA levels and attention-deficit hyperactivity disorder or depression. Here, we summarize the main findings regarding the association between n-3 PUFA and hyperactive and emotional disorders, and discuss potential mechanisms of action. Because the basal ganglia are involved in the control of locomotion and emotion, we examined published data regarding the role of n-3 PUFA in dopamine (DA) regulation in the basal ganglia. These results are discussed in the light of recent data from our laboratory suggesting an association between the drop in melatonin in the pineal gland and the increase in DA in the striatum and nucleus accumbens of n-3 PUFA-deprived rodents.