Objective The purpose of this study was to evaluate the effect of altitude on rates of ADHD. As decreased dopamine (DA) activity has been reported with ADHD and hypoxia has shown to be associated with increased DA, we hypothesized that states at higher altitudes would have lower rates of ADHD. Method State estimates from the 2007 National Survey of Children’s Health (NSCH) report and 2010 National Survey of Children with Special Health Care Needs (NS-CSHCN) report were used to extract the percentages of youth ages 4 to 17 diagnosed with ADHD. Results Both the datasets independently revealed that the prevalence of ADHD decreases with increasing altitude (R2 = .38, p < .001; R2 = .31, p < .001), respectively. This study controlled for potential confounds (e.g., low birth weight, ethnicity, and household size). Conclusion These findings suggest a need for further investigation into the extent by which altitude may serve as a protective factor for ADHD.

Background Delayed diagnosis in bipolar disorder (BD) due to misdiagnosis as major depressive disorder (MDD) is a significant public health concern. Thus, identification of relevant diagnostic biomarkers is a critical unmet need, particularly early in the course of illness. The anterior cingulate cortex (ACC) is thought to play an important role in mood disorder pathophysiology. Case-control studies utilizing proton-1 magnetic resonance spectroscopy (1H-MRS) have found increased total choline levels in several brain regions in MDD. However, there are no published 1H-MRS reports directly comparing adolescents with MDD and BD. We hypothesized that ACC choline levels would be increased in adolescents with unipolar versus bipolar depression. Methods We studied depressed adolescents with MDD (n=28; mean age 17.0±2.1 years) and BD (n=9; 17.3±3.1 years). A Siemens Verio 3-Tesla clinical MRI system was used to acquire scans, using a single-voxel PRESS sequence. The voxel (18.75 cm3) was positioned on the ACC in the midsagittal plane. To remove potential gender effects, only female adolescent participants were included. Data were analyzed using the ANOVA and post-hoc Tukey tests. Results A significantly increased ACC choline/creatine ratio was observed in participants with MDD (mean=0.253±0.021) compared to BD (mean=0.219±0.020) (p=0.0002). There were no significant differences in the other 1H-MRS metabolites. Limitations Cross sectional design, single gender sample, limited sample size. Conclusions The present findings suggest that ACC total choline may have the potential to serve as a diagnostic biomarker in adolescent mood disorders.