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In This Issue of JAMA Psychiatry
June 2018


JAMA Psychiatry. 2018;75(6):539. doi:10.1001/jamapsychiatry.2017.2982


Depression is among the most disabling medical conditions in the world, yet there is still no objective prognostic marker of severity. In this randomized clinical trial, Pizzagalli and colleagues examined the electroencephalogram θ activity of 248 of 266 individuals with depression who had been randomized to sertraline or placebo. Greater current θ activity density localized over the rostral anterior cingulate at both baseline, and week 1 predicted greater improvement in depressive symptoms, even when controlling for clinical and demographic variables previously linked to treatment response.

The benefits of resistance exercise training are well documented, but no synthesis of its antidepressant effects has been conducted. In this meta-analysis, Gordon and colleagues examined 33 studies reporting on more than 1800 participants and found that resistance exercise training was associated with a moderate-sized significantly antidepressant effect compared with nonactive control conditions, regardless of health status or improvements in strength, with a number needed to treat of 4. These results indicate that resistance exercise training should be studied further along with other empirically supported treatments for depressive symptoms.

Continuing Medical Education

Perceived harm from cannabis use has decreased in recent years, but the effects of cannabis use on cognitive functioning in youths has not been systematically examined. Scott and colleagues conducted a meta-analysis of 69 studies including 2152 cannabis users and 6575 comparison participants and found a small adverse effect of cannabis on cognitive function in heavy users; this effect disappeared in studies requiring an abstinence period of more than 72 hours. The association between cannabis use and cognitive functioning is small and likely to be of questionable clinical importance for most individuals.

Bullying by peers has been associated with disordered eating and depression among adolescents, but the associations between these phenomena have not been studied over time. In a longitudinal cohort study, Lee and Vaillancourt followed 612 teenagers starting at age 10 years and found that bullying was associated with disordered eating and depressive symptoms at each time, while disordered eating was a risk factor for future depressive symptoms and bullying. These results highlight problematic eating behavior as an intervention target to attenuate the risk of future depression and relational problems.

No reliable biological marker has been identified to predict which clinical high-risk individuals will develop psychosis symptoms. Das and colleagues used magnetic resonance imaging to study healthy control individuals and at-risk individuals who later did or did not develop psychosis as well as first-episode psychosis patients and found that small-worldness in a gyrification-based network was reduced in at-risk individuals who later developed psychosis compared with those who did not. Thus, poor integration in development of cortical folding delineates at-risk individuals who develop psychosis.