The effect of time outdoors on veterans receiving treatment for PTSD.

OBJECTIVES: Duration, frequency, and intensity of nature exposure link to different physical and psychological benefits. The present study aimed to determine how time outdoors affected military veterans' posttraumatic stress disorder (PTSD) symptomology during PTSD treatment. METHOD: Hypotheses regarding time outdoors and the effect of program duration on PTSD symptoms were examined using multilevel models. The authors hypothesized that hours outdoors, both within- and between-persons, would predict reduced PTSD symptomology, program duration would predict reduced PTSD symptomology, and that hours outdoors and program duration would be significant when accounting for the other. RESULTS: The present study found that time outdoors correlated with participants' decreased PTSD symptomology: the more time participants spent outdoors, the greater the reduction in their PTSD symptoms. CONCLUSION: The effect of time outdoors was significant within-person, not between persons, suggesting that nature exposure may be used as an adjunct to traditional mental health treatment where exposure or dosage should be person-specific.

An acute, epitope-specific modification in the dopamine transporter associated with methamphetamine-induced neurotoxicity.

Preclinical studies demonstrate that repeated, high-dose methamphetamine administrations rapidly decrease plasmalemmal dopamine uptake, which may contribute to aberrant dopamine accumulation, reactive species generation, and long-term dopaminergic deficits. The present study extends these findings by demonstrating a heretofore unreported, epitope-specific modification in the dopamine transporter caused by a methamphetamine regimen that induces these deficits. Specifically, repeated, high-dose methamphetamine injections (4 × 10 mg/kg/injection, 2-h intervals) rapidly decreased immunohistochemical detection of striatal dopamine transporter as assessed 1 h after the final methamphetamine exposure. In contrast, neither a single high dose (1 × 10 mg/kg) nor repeated injections of a lower dose (4 × 2 mg/kg/injection) induced this change. The high-dose regimen-induced alteration was only detected using antibodies directed against the N-terminus. Immunohistochemical staining using antibodies directed against the C-terminus did not reveal any changes. The high-dose regimen also did not alter dopamine transporter expression as assessed using [(125) I]RTI-55 autoradiography. These data suggest that the repeated, high-dose methamphetamine regimen alters the N-terminus of the dopamine transporter. Further, these data may be predictive of persistent dopamine deficits caused by the stimulant. Future studies of the signaling cascades involved should provide novel insight into potential mechanisms underlying the physiological and pathophysiological regulation of the dopamine transporter.