Prenatal exposure to polycyclic aromatic hydrocarbons has been associated with cognitive disturbances in childhood. Peterson and coauthors studied brain structure, cognition, and behavior in 40 minority urban children followed up prospectively from the fetal period. They detected a dose-response relationship between prenatal polycyclic aromatic hydrocarbon exposure and reduced left hemisphere white matter, which was associated with slower information processing speed. In a Viewpoint, Calderón-Garcidueñas and Torres-Jardón discuss the impact of air pollutants on the brain.
Military deployment has been debated to increase suicide risk in service members. Reger and coauthors used a retrospective cohort design to study suicide mortality in 3.9 million US military personnel who served during Operation Enduring Freedom or Operation Iraqi Freedom. Deployment was not associated with the rate of suicide but the rate of suicide increased after an early separation from the military service and when discharge was not honorable.
Adult attention-deficit/hyperactivity disorder (ADHD) is present in almost 1 of every 4 patients with substance use disorder. Levin and coauthors conducted a clinical trial in adult patients with cocaine use disorder (CUD) and comorbid ADHD to study the effect of extended-release mixed amphetamine salts (60 mg or 80 mg) or placebo daily for 13 weeks. The medication group showed improved ADHD symptoms and reduced cocaine use, supporting the closely monitored use of stimulants in patients with substance use disorder and co-occurring ADHD.
Major depressive disorder has been linked to abnormal communication between various brain regions. Kaiser and coauthors used meta-analytic methods to investigate network dysfunction in data sets from 25 publications. They found decreased connectivity in networks governing attention and emotion regulation but increased connectivity in networks governing self-referential thought. This may reflect depressive biases toward internal thoughts at the cost of engaging with the world.
Depression and type 2 diabetes mellitus are risk factors for dementia but their combined effect on dementia has not been studied. Katon and coauthors performed a population-based cohort study of more than 2.4 million Danish adults. They found that both depression and type 2 diabetes mellitus increased the risk for dementia but that the combined effect was much stronger than the additive association. This was especially true for individuals younger than 65 years. In an Invited Commentary, Reynolds discusses the importance of promoting healthy brain aging.
Continuing Medical Education
Highlights. JAMA Psychiatry. 2015;72(6):525. doi:10.1001/jamapsychiatry.2014.1888