Journal Digest

A long-running study that followed children with attention-deficit/hyperactivity disorder (ADHD) for over 30 years has identified some features that might predict how children with ADHD will fare as adults.

As described in the Journal of the American Academy of Child & Adolescent Psychiatry in June, investigators at New York University Langone Medical Center and colleagues examined various clinical and behavioral traits of 135 boys with ADHD who were prospectively followed into adulthood (mean age 41).

The researchers found that higher childhood IQ was associated with four of the five adult outcomes measured: educational attainment, occupational rank, occupational functioning, and social functioning; overall functioning was not linked with IQ. Two other childhood characteristics—socioeconomic status and reading ability—were positively associated with educational attainment. In contrast, childhood conduct problems, even if low severity, were negatively associated with overall function, educational attainment, and occupational functioning.

Among the adolescent characteristics, antisocial behavior was associated with poorer educational attainment while having strong educational goals was related to better overall functioning.

The findings demonstrate “the importance of goal setting and suggest a rationale for examining people’s attitudes toward their own future,” the authors wrote.

Fatigue is a debilitating condition that affects many cancer patients (both from the effects of the disease as well as its treatment), yet little is known about the underlying mechanisms of cancer-related fatigue. A study appearing in Translational Psychiatry indicates the glutamate receptor mGluR5 may be a key mediator of fatigue in cancer patients.

Investigators at the National Institute of Nursing Research and colleagues examined the gene expression profiles of blood cells from 36 men with prostate cancer, 12 of whom developed significant fatigue one year after receiving radiation therapy. Several genes related to glutamate signaling, including mGluR5, were more highly expressed in the fatigued men compared with those who did not experience fatigue.

The researchers then treated healthy cell cultures with either a mGluR5 activator, mGluR5 inhibitor, or saline before exposing the cells to radiation. Prior to radiation exposure, there were no significant differences in the treated cells (aside from mGluR5 levels). Following radiation, the control cells showed a high degree of mGluR5 proteins clustering together, which triggered the expression of other proteins associated with inflammation; this mGluR5 clustering was even higher in cells pretreated with the mGluR5 activator. Cells given the mGluR5 inhibitor displayed minimal levels of clustering and immune activation after radiation.

“These results suggest that mGluR5 signaling in T cells may play a key role in the development of chronic inflammation resulting in fatigue and contribute to individual differences in immune responses to radiation,” the authors wrote. “[M]odulating mGluR5 provides a novel therapeutic option to treat CRF [cancer-related fatigue].”

Researchers at the University of California, Davis, have used functional magnetic resonance imaging (fMRI) to show, for the first time, brain activity related to memory recall in toddlers.

While studies have suggested that the development of the hippocampus is key to the emergence of episodic memory in young children, researchers have been limited in their ability to track this development.

The investigators developed a protocol that enabled them to take fMRI scans of 22 normally developing toddlers (aged 25 to 32 months) while they slept at night. During the tests, the investigators played recordings of songs, including a mix of songs the toddlers had heard while playing with toys in the lab and other unfamiliar tunes.

The researchers found that activity in the hippocampus (a center for learning and memory) was greatest when the sleeping toddlers heard a familiar song. The toddlers with the highest hippocampal activity showed a better ability to recall the context of the song; that is, they remembered which room they had heard the song in and/or which toy they were playing with at the time.

The study “offers an initial glimpse at how the hippocampus supports memory in early life and sets the foundation for further explorations of the neural representations that support early development,” the study authors wrote.

Their findings were published in PNAS in June.

Psychiatric disorders do not affect the success of weight loss following bariatric surgery in children, according to a study in Pediatrics.

Researchers at George Washington University assessed 169 adolescents three and 12 months after the youth had bariatric surgery. All the children had been referred for psychological evaluation prior to surgery, and around 70 percent of the participants were diagnosed with a psychiatric condition, including anxiety, attention-deficit/hyperactivity disorder (ADHD), depression, and eating disorders.

After controlling for demographic factors, the researchers found no differences in weight loss outcomes for adolescents who had been diagnosed with psychiatric disorders before surgery and those who had not.

“Unlike other interventions that may be influenced by cultural or socioeconomic factors, surgical intervention appears to offer all kids the same opportunity to succeed,” said lead author Eleanor Mackey, Ph.D., in a press release. “Most important, there’s no scientific basis for denying an adolescent this procedure based simply on the presence of a psychiatric disorder. This does not mean adolescents should not be evaluated and treated for these disorders, which themselves have a significant impact on functioning and quality of life, but in terms of weight loss after surgery, the presence of psychiatric disorders is not predictive of outcomes.”

Previous research has found a link between living at higher altitudes and depression risk. A study in rats now suggests the antidepressants escitalopram, fluoxetine, and paroxetine may be less effective at high elevations.

Researchers at the University of Utah created high-altitude conditions for male and female rats by housing rats at oxygen levels comparable to altitudes of 4,500 feet or 10,000 feet above sea level. After about a week, the animals displayed more inactive, depressive-like behaviors.

The rats were then treated with the tricyclic antidepressant desipramine or one of four SSRIs: escitalopram, fluoxetine, paroxetine, and sertraline. Animals who were treated with desipramine and sertraline displayed reduced depressive-like behaviors; in contrast, exposure to fluoxetine led to no changes in depressive behaviors in male rats. Escitalopram and paroxetine were found to be ineffective in both male and female rats.

The study authors noted that low oxygen can reduce brain levels of serotonin, which might explain why some of the SSRIs were less effective. As for sertraline, it’s efficacy could be a result of its ability to improve both serotonin and dopamine transmission, they wrote.

This study was published in Pharmacology, Biochemistry and Behavior. ■