[A long-term qualitative behavioral change following chronic methamphetamine administration in Japanese monkeys...

Changes in spontaneous behavior and behavioral response to various neuroactive agents following chronic methamphetamine (MAP) administration were assessed in 3 monkeys. The results obtained were: 1) daily administration of MAP (1 mg/kg) for 12 weeks resulted in a progressive qualitative alteration of behavior content including increased inhibition and staring, 2) such abnormal behavior was augmented during the chronic treatment and was reappeared by a test dose (0.2 mg/kg) of MAP after 2 or 4 weeks of abstinence, 3) a progressive increase in behavioral stereotypy was not observed during the chronic treatment, 4) challenge with test doses of various agents showed positive cross sensitization to cocaine, whereas saline and dopamine agonists such as apomorphine and L-Dopa failed to reproduce the same abnormal behavior as MAP-induced one, and 5) behavioral responses to dopamine agonists was changed while negative cross sensitization to 5-HTP was found following the chronic MAP treatment. It was suggested that both disturbance of contact to external environment, and its progressive augmentation rather than behavioral stereotypy may be more critical for MAP model of psychosis, and that dopaminergic supersensitivity may be a part of biological change underlying such MAP-induced behavioral changes.