OBJECTIVE: Methamphetamine (MA) use rates in the United States (US) have consistently demonstrated geographical variation and have been higher in the West and Midwest. This uneven pattern of use could be explained by regional differences in MA manufacturing and distribution, but may also result from differences in altitude. The hypobaric hypoxia found at high altitude alters neurotransmitter synthesis in the brain, which may contribute to MA use. The present study investigated the relationship between mean altitude and MA use rate in the 48 contiguous US states and the District of Columbia. METHODS: State-level estimates of past year MA use were extracted from the National Survey on Drug Use and Health report. The mean altitude of each state was calculated using the Shuttle Radar Topography Mission altitude data set. RESULTS: There was a significant positive correlation between mean state altitude and MA use rate (r=0.66, p<0.0001). Multivariate linear regression analysis showed that altitude remained a significant predictor for MA use rate (beta=0.36, p=0.02), after adjusting for age, ethnicity, education, socioeconomic level, employment, MA laboratory incidents, subpopulations, and other substance use. CONCLUSION: Altitude appears to a possible contributing factor for regional variation of MA use in the US. Further studies will be required to determine biological changes in neurotransmission resulting from chronic mild hypoxia at high altitude in MA users.
Altitude* ; Anoxia ; Brain ; Dataset ; Education ; Employment ; Humans ; Linear Models ; Methamphetamine* ; Missions and Missionaries ; Neurotransmitter Agents ; Synaptic Transmission ; United States*

Objective: The purpose of this study was to explore the capacity for energy production under conditions of increased energy demand in schizophrenia (SCZ) subjects compared to healthy controls. Methods: Twelve healthy controls (33.00±6.07 years) and 12 subjects diagnosed with SCZ or schizoaffective disorder (36.00±8.33 years) matched for age and sex, were recruited for this study. Hypoxic stress was induced during MR scans to elevate the energy demand on the subjects’ bioenergetic systems. Participants breathed air with a lower oxygen concentration (FiO2=13%), maintaining their SpO2 levels (86%) during the initial phase of the scan. 31Phosphorus MR spectroscopy was employed to examine metabolite levels, including phosphocreatine (PCr), β-adenosine triphosphate (ATP), and inorganic phosphate (Pi), as well as the ratios of PCr/Pi and PCr/β-ATP, in regions such as the prefrontal cortex (PFC), anterior cingulate cortex (ACC), and posterior cortex (POC), as well as across the entire brain, during both hypoxia and hyperoxia scans. Results: Subjects with SCZ had significantly lower levels of Pi across the brain and particularly, in the PFC, POC, and ACC during the hypoxia scan. Moreover, levels of PCr/Pi, indicative of mitochondrial energy production, were found to be higher in the same brain regions in the SCZ group. No significant differences were found in hyperoxia scan phase. Conclusion These findings suggest a deficit in the bioenergetic systems of individuals with SCZ under conditions of heightened energy demand. Further studies are warranted.

Objective: The purpose of this study was to explore the capacity for energy production under conditions of increased energy demand in schizophrenia (SCZ) subjects compared to healthy controls. Methods: Twelve healthy controls (33.00±6.07 years) and 12 subjects diagnosed with SCZ or schizoaffective disorder (36.00±8.33 years) matched for age and sex, were recruited for this study. Hypoxic stress was induced during MR scans to elevate the energy demand on the subjects’ bioenergetic systems. Participants breathed air with a lower oxygen concentration (FiO2=13%), maintaining their SpO2 levels (86%) during the initial phase of the scan. 31Phosphorus MR spectroscopy was employed to examine metabolite levels, including phosphocreatine (PCr), β-adenosine triphosphate (ATP), and inorganic phosphate (Pi), as well as the ratios of PCr/Pi and PCr/β-ATP, in regions such as the prefrontal cortex (PFC), anterior cingulate cortex (ACC), and posterior cortex (POC), as well as across the entire brain, during both hypoxia and hyperoxia scans. Results: Subjects with SCZ had significantly lower levels of Pi across the brain and particularly, in the PFC, POC, and ACC during the hypoxia scan. Moreover, levels of PCr/Pi, indicative of mitochondrial energy production, were found to be higher in the same brain regions in the SCZ group. No significant differences were found in hyperoxia scan phase. Conclusion These findings suggest a deficit in the bioenergetic systems of individuals with SCZ under conditions of heightened energy demand. Further studies are warranted.

Objective: The purpose of this study was to explore the capacity for energy production under conditions of increased energy demand in schizophrenia (SCZ) subjects compared to healthy controls. Methods: Twelve healthy controls (33.00±6.07 years) and 12 subjects diagnosed with SCZ or schizoaffective disorder (36.00±8.33 years) matched for age and sex, were recruited for this study. Hypoxic stress was induced during MR scans to elevate the energy demand on the subjects’ bioenergetic systems. Participants breathed air with a lower oxygen concentration (FiO2=13%), maintaining their SpO2 levels (86%) during the initial phase of the scan. 31Phosphorus MR spectroscopy was employed to examine metabolite levels, including phosphocreatine (PCr), β-adenosine triphosphate (ATP), and inorganic phosphate (Pi), as well as the ratios of PCr/Pi and PCr/β-ATP, in regions such as the prefrontal cortex (PFC), anterior cingulate cortex (ACC), and posterior cortex (POC), as well as across the entire brain, during both hypoxia and hyperoxia scans. Results: Subjects with SCZ had significantly lower levels of Pi across the brain and particularly, in the PFC, POC, and ACC during the hypoxia scan. Moreover, levels of PCr/Pi, indicative of mitochondrial energy production, were found to be higher in the same brain regions in the SCZ group. No significant differences were found in hyperoxia scan phase. Conclusion These findings suggest a deficit in the bioenergetic systems of individuals with SCZ under conditions of heightened energy demand. Further studies are warranted.

Objective: The purpose of this study was to explore the capacity for energy production under conditions of increased energy demand in schizophrenia (SCZ) subjects compared to healthy controls. Methods: Twelve healthy controls (33.00±6.07 years) and 12 subjects diagnosed with SCZ or schizoaffective disorder (36.00±8.33 years) matched for age and sex, were recruited for this study. Hypoxic stress was induced during MR scans to elevate the energy demand on the subjects’ bioenergetic systems. Participants breathed air with a lower oxygen concentration (FiO2=13%), maintaining their SpO2 levels (86%) during the initial phase of the scan. 31Phosphorus MR spectroscopy was employed to examine metabolite levels, including phosphocreatine (PCr), β-adenosine triphosphate (ATP), and inorganic phosphate (Pi), as well as the ratios of PCr/Pi and PCr/β-ATP, in regions such as the prefrontal cortex (PFC), anterior cingulate cortex (ACC), and posterior cortex (POC), as well as across the entire brain, during both hypoxia and hyperoxia scans. Results: Subjects with SCZ had significantly lower levels of Pi across the brain and particularly, in the PFC, POC, and ACC during the hypoxia scan. Moreover, levels of PCr/Pi, indicative of mitochondrial energy production, were found to be higher in the same brain regions in the SCZ group. No significant differences were found in hyperoxia scan phase. Conclusion These findings suggest a deficit in the bioenergetic systems of individuals with SCZ under conditions of heightened energy demand. Further studies are warranted.

Objective: The purpose of this study was to explore the capacity for energy production under conditions of increased energy demand in schizophrenia (SCZ) subjects compared to healthy controls. Methods: Twelve healthy controls (33.00±6.07 years) and 12 subjects diagnosed with SCZ or schizoaffective disorder (36.00±8.33 years) matched for age and sex, were recruited for this study. Hypoxic stress was induced during MR scans to elevate the energy demand on the subjects’ bioenergetic systems. Participants breathed air with a lower oxygen concentration (FiO2=13%), maintaining their SpO2 levels (86%) during the initial phase of the scan. 31Phosphorus MR spectroscopy was employed to examine metabolite levels, including phosphocreatine (PCr), β-adenosine triphosphate (ATP), and inorganic phosphate (Pi), as well as the ratios of PCr/Pi and PCr/β-ATP, in regions such as the prefrontal cortex (PFC), anterior cingulate cortex (ACC), and posterior cortex (POC), as well as across the entire brain, during both hypoxia and hyperoxia scans. Results: Subjects with SCZ had significantly lower levels of Pi across the brain and particularly, in the PFC, POC, and ACC during the hypoxia scan. Moreover, levels of PCr/Pi, indicative of mitochondrial energy production, were found to be higher in the same brain regions in the SCZ group. No significant differences were found in hyperoxia scan phase. Conclusion These findings suggest a deficit in the bioenergetic systems of individuals with SCZ under conditions of heightened energy demand. Further studies are warranted.