Prenatal marijuana exposure and visual perception in toddlers: Evidence of a sensory processing deficit.

Background: Research has identified a link between prenatal marijuana exposure and multiple outcomes in children, including cognitive development. Several studies have found specific differences in sensory processing and attention, with visual perception especially impacted in school age children. The current study explored whether this effect is evident at an earlier age, and thus our goal was to investigate the relationship between in-utero marijuana exposure and sensory processing capabilities in toddlers. We hypothesized that in-utero marijuana exposure throughout pregnancy would specifically predict visual sensory hyperactivity in children as young as 15 months of age. Methods: Participants were 225 15-month-old children whose mothers were recruited during pregnancy. Substance exposure was prospectively collected and biochemically verified, with marijuana coded as no exposure, 1st trimester exposure only, or exposure throughout pregnancy. The Infant Toddler Sensory Profile evaluated 5 domains of sensory processing (visual, auditory, tactile, vestibular, oral). Results: Prenatal marijuana exposure throughout pregnancy, but not when limited to the first trimester, predicted a two-fold increased likelihood of scoring in a range indicating high levels of seeking out and potentially over-attending to visual stimulation after controlling for potentially confounding factors including other prenatal exposures. Marijuana exposure was not significantly related to other processing domains. Conclusion: Results indicate that links previously identified between prenatal marijuana exposure and visual function and attention may already be evident at 15 months of age, and also suggest an impact related to continuous/later pregnancy exposure. Our findings, as well as those from previous studies, all suggest visual processing differences for exposed children, differences that may predict emerging issues with visual attention and habituation. As legalization of marijuana continues to increase, further research is clearly needed to examine specific teratologic effects associated with use during pregnancy.

A d factor? Understanding trait distractibility and its relationships with ADHD symptomatology and hyperfocus.

People differ substantially in their vulnerability to distraction. Yet, many types of distractions exist, from external stimulation to internal thoughts. How should we characterize individual differences in their distractibility? Two samples of adult participants (total N = 1220) completed a large battery of questionnaires assessing different facets of real-world distractibility. Latent modeling revealed that these measures could be explained by three correlated-yet-distinct factors: external distraction, unwanted intrusive thoughts, and mind-wandering. Importantly, about 80% of the total variance in these three factors could be explained by a single higher-order factor (d) that could be construed in terms of a person's general distractibility, and this general distractibility model was replicated across the two samples. We then applied the general distractibility model to understand the nature of ADHD symptomatology and hyperfocus (an intense state of long-lasting and highly focused attention). d was substantially associated with self-reported ADHD symptoms. Interestingly, d was also positively associated with hyperfocus, suggesting that hyperfocus may, to some degree, reflect attention problems. These results also show marked consistencies across the two samples. Overall, the study provides an important step toward a comprehensive understanding of individual differences in distractibility and related constructs.

The association between different sources of distraction and symptoms of attention deficit hyperactivity disorder.

Introduction: Adults with Attention-Deficit/Hyperactivity Disorder (ADHD) are generally distractible. Yet, the precise relationship between ADHD and distractibility remains under-specified in two respects. First, different sources of distraction, such as background noise or mind wandering, may not be equally associated with ADHD. Second, ADHD itself comprises a variety of symptoms that show considerable heterogeneity and it is unclear which ADHD symptoms are associated with which type of distraction. Methods: The current study addresses these questions using one clinically evaluated sample (N = 69) and two large non-clinically evaluated samples (N = 569, N = 651). In all samples, participants completed questionnaires about their susceptibility to external distraction, unwanted intrusive thoughts, spontaneous mind-wandering and ADHD symptomatology. Results: Traditional regression and novel network analyses revealed an overwhelming contribution of spontaneous mind-wandering in explaining ADHD symptoms, although external distraction and unwanted intrusive thoughts were also associated with a small number of ADHD symptoms. Discussion: Findings support a growing body of literature linking spontaneous mind-wandering and ADHD, and they highlight the heterogeneity in the association between ADHD symptoms and different sources of distraction.

Does it matter when I quit? Could I just cut down some? Links between trimester-specific smoking amount, preterm birth, and low birth weight.

BACKGROUND: Substantial evidence demonstrates the harms of pregnancy smoking. Due to the need for very large data sets, less data exist to inform decisions about when quitting should occur, or whether a certain amount of reduction is beneficial. OBJECTIVES: Our goal was to examine the effect of timing and amount of pregnancy smoking on low birth weight (LBW) and preterm birth (PTB). METHODS: Data for 3 years of registered births in Tennessee were available and included standard birth certificate information. RESULTS: Of 241,616 women, 15.7% smoked at conception, and those who quit as early as the first trimester had significantly increased adjusted odds of LBW (27%) and PTB (14%) compared to nonsmokers, with this effect largely driven by smoking 10+ cigarettes per day. Smoking into the second trimester but quitting prior to the third also predicted increases in LBW and PTB compared to both not smoking at all and smoking only in the first trimester. Smoking to delivery predicted a 2.8-fold increased likelihood of LBW, and a 2.1-fold increased rate of PTB. Any level of smoking after the first trimester substantially increased the odds of poor outcomes compared to both nonsmoking and smoking only in the first trimester. CONCLUSIONS: Findings suggest that to avoid LBW or PTB, pregnant smokers should be advised that quitting completely by the end of the first trimester is important, and that continuing to smoke even <5 cigarettes per day after that point substantially increases the potential for of adverse outcomes.