Skip to main content
eScholarship
Open Access Publications from the University of California

Scholarly Works (8 results)

  • Article
  • Peer Reviewed
UC Irvine Previously Published Works (2013)
Individuals with attention-deficit/hyperactivity disorder (ADHD) have elevated smoking prevalence and reduced cessation rates compared to the general population. However, the effects of cigarette smoking on underlying brain activity in smokers with ADHD are not well characterized. Non-invasive near-infrared spectroscopy (NIRS) was used to characterize how cigarette smoking affects prefrontal brain hemodynamics in smokers with and without ADHD. Prefrontal changes of oxy- and deoxyhemoglobin (HbO2 and HHb) were measured in six male adult smokers with ADHD and six age- and gender-matched control smokers. NIRS measurements were separated into four sequential time intervals, i.e., before smoking, during smoking, after smoking, and during a breath hold. Prefrontal HbO2 was lower during smoking in smokers with ADHD compared to control smokers. More specifically, smokers with ADHD showed decreased prefrontal HbO2 during smoking compared to breath hold, before and after smoking periods. In contrast, control smokers showed increased prefrontal HbO2 from before smoking to breath hold. Decreased prefrontal HbO2 in smokers with ADHD may reflect a smoking-induced change in prefrontal brain activity and microvasculature, which is not found in smokers without ADHD. The lower prefrontal HbO2 may be a biomarker for increased susceptibility to tobacco smoke in smokers with ADHD. Smoking in individuals with ADHD may increase vasoconstriction of cerebral arteries in the prefrontal cortex, which may contribute to a reduction in HbO2. The findings highlight the importance of smoking cessation, in particular in those smokers who use nicotine to self-medicate ADHD symptoms.
    Cover page: Prefrontal hemodynamic changes during cigarette smoking in young adult smokers with and without ADHDCreative Commons 'BY' version 4.0 license
    • Article
    • Peer Reviewed
    UC Irvine Previously Published Works (2019)
    Objective: Attention-deficit/hyperactivity disorder (ADHD) is associated with an increased smoking prevalence and impairments in executive function, which may negatively affect the validity of self-reported smoking rates. This study compares the utility of self-reported smoking with salivary cotinine in adult smokers and nonsmokers with and without ADHD. Methods: Participants (N = 82) were adult smokers and nonsmokers with and without ADHD (n = 35 ADHD and n = 47 controls) from an observational study. Odds ratios (ORs) for accuracy of self-reported smoking compared to salivary cotinine were calculated using diagnosis (ADHD vs. control), gender, age, education, employment, and number of cigarettes per day as predictors. Post-hoc analysis stratified sensitivity, specificity, and accuracy of self-reported smoking in individuals with ADHD and without ADHD. Results: The initial analysis identified education as a significant independent predictor of odds of accuracy, OR = 6.22, p = .013, after adjusting for diagnosis, gender, age, employment, and cigarettes per day. Post-hoc analysis revealed that sensitivity, specificity, and accuracy of self-reported smoking was 100% for individuals with ADHD who had more than high school education compared to those with high school or less, which was 83.3%, 45.5%, and 65.2%, respectively. Self-reported smoking of control participants with greater than a high school education had a sensitivity of 85.7%, a specificity of 91.7%, and an accuracy of 88.5%. Control participants with a high school or lower education had a sensitivity of 54.6%, a specificity of 90%, and an accuracy of 71.4% for their self-reported smoking. Conclusions: Individuals with ADHD and high school or lower education showed the lowest specificity and accuracy in their self-reported smoking, which may affect documented smoking prevalence rates. This is a secondary analysis of data collected as part of a clinical trial registered as NCT00915798 at www.clinicaltrials.gov .
      Cover page: Discrepancies in the Validity of Self-Reported Cigarette Smoking in Adults With and Without ADHD
      • Article
      • Peer Reviewed
      ICTS Publications (2011)

      Individuals with ADHD may self-medicate with nicotine, the main psychoactive ingredient in tobacco smoke, in order to reduce symptoms and negative moods associated with ADHD. ADHD medication (e.g., methylphenidate and atomoxetine) may mimic some of the effects of nicotine and may aid smoking cessation in smokers with ADHD. The present study examined if ADHD medication reduces smoking and withdrawal in non-treatment seeking smokers with ADHD. Fifteen adult smokers with ADHD participated in the study, which consisted of an experimental phase and field monitoring phase to examine the acute and extended effects, respectively, of ADHD medication. During the experimental phase, smokers were asked to complete a Continuous Performance Task (CPT) and the Shiffman-Jarvik smoking withdrawal questionnaire during the following four conditions: (1) ADHD medication+cigarette smoking, (2) ADHD medication+overnight abstinence, (3) placebo+cigarette smoking, and (4) placebo+overnight abstinence. During the field monitoring phase, participants were asked to provide salivary cotinine samples and complete electronic diaries about smoking, smoking urge, ADHD symptoms, and stress in everyday life for two days on ADHD medication and for two days on placebo. Results of the experimental phase showed that ADHD medication improved task performance on the CPT and reduced withdrawal during overnight abstinence. During the field monitoring phase, ADHD medication reduced salivary cotinine levels compared to placebo. In addition, the electronic diary revealed that ADHD medication improved difficulty concentrating during no smoking events and stress. The findings of the present study suggest that, along with other strategies, ADHD medication may be used to aid smoking withdrawal and cessation in smokers with ADHD.

      • 1 supplemental PDF
      Cover page: ADHD medication reduces cotinine levels and withdrawal in smokers with ADHD.
      • Article
      • Peer Reviewed
      ICTS Publications (2017)

      This is one of the first studies to examine the structural brain anatomy and connectivity associated with an ADHD diagnosis and child as well as adult ADHD symptoms in young adults. It was hypothesized that an adult ADHD diagnosis and in particular childhood symptoms, are associated with widespread changes in the brain macro- and microstructure, which can be used to develop a morphometric biomarker for ADHD.

      Voxel-wise linear regression models were used to examine structural and diffusion-weighted MRI data in 72 participants (31 young adults with ADHD and 41 controls without ADHD) in relation to diagnosis and the number of self-reported child and adult symptoms.

      Findings revealed significant associations between ADHD diagnosis and widespread changes to the maturation of white matter fiber bundles and gray matter density in the brain, such as structural shape changes (incomplete maturation) of the middle and superior temporal gyrus, and fronto-basal portions of both frontal lobes. ADHD symptoms in childhood showed the strongest association with brain macro- and microstructural abnormalities. At the brain circuitry level, the superior longitudinal fasciculus (SLF) and cortico-limbic areas are dysfunctional in individuals with ADHD. The morphometric findings predicted an ADHD diagnosis correctly up to 83% of all cases.

      An adult ADHD diagnosis and in particular childhood symptoms are associated with widespread micro- and macrostructural changes. The SLF and cortico-limbic findings suggest complex audio-visual, motivational, and emotional dysfunctions associated with ADHD in young adults. The sensitivity of the morphometric findings in predicting an ADHD diagnosis was sufficient, which indicates that MRI-based assessments are a promising strategy for the development of a biomarker.

        Cover page: The brain anatomy of attention-deficit/hyperactivity disorder in young adults - a magnetic resonance imaging study.Creative Commons 'BY' version 4.0 license
        • Article
        • Peer Reviewed
        UC Irvine Previously Published Works (2023)
        Anxiety is a common comorbidity for individuals with ASD, and there is some preliminary data about the efficacy of physical exercise to alleviate anxiety. However, we are not aware of any studies that have compared the effects of a physical exercise program on anxiety in underserved children with ASD using a randomized controlled research design. This paper describes a method to evaluate and compare the efficacy of an 8-week physical exercise intervention with a sedentary play intervention to alleviate anxiety in young children with autism spectrum disorders (ASD) from underserved backgrounds. We assessed anxiety and its physical symptoms using the parent-rated Child Behavior Checklist DSM-5 anxiety (CBCL DSM-5) subscale, the child-rated Screen for Childhood Anxiety Related Emotional Disorder (SCARED), the parent-rated Child's Sleep Habits Questionnaire (CSHQ), and salivary cortisol. We also utilized the Physical Activity Questionnaire for Older Children (PAQ-C) to assess physical activity level and identify compounds. Unique components of this study include: •Implementation of novel physical exercise and sedentary play interventions that have been designed for children with ASD.•Recruitment of predominantly underserved and non-English speaking families.
          Cover page: Effects of physical exercise, LEGO, and Minecraft activities on anxiety in underserved children with autism: Study design and methodological strategies
          • Article
          • Peer Reviewed
          UC Irvine Previously Published Works (2020)
          Physical activity may improve symptoms and skill deficits associated with autism spectrum disorder (ASD). The objective of this study was to compare the reported frequency of physical activity and covariates in a large sample of children with ASD with children of similar age from the general population. The sample with ASD was derived from the Autism Treatment Network Registry Call Back Assessment (n = 611), and the general population data were derived from the National Survey of Childrens Health (NSCH) (n = 71,811). In addition, demographic, child, and family (parent) factors were examined in relation to frequency of recent physical activity in children with ASD. Among males in the 6-11 year-old age group, those with ASD participated in physical activity less often (p <0.001) than those in the NSCH general population. Specifically, 33 % of boys 6-11 years old in the NSCH group vs. only 17 % in the RCBA group 6-11 years old engaged in some physical activity every day, while 4 % of boys in the NSCH group vs. 18 % in the RCBA group engaged in no physical activity whatsoever. A similar effect was seen across other age groups and in females but was not statistically significant. The demographic, child, and family characteristics associated with physical activity in children and adolescents with ASD included ethnicity in females, DSM-IV ASD diagnosis, IQ, and PAM-13 total score in females. Parents and caregivers are encouraged to find suitable physical activity programs for children with ASD. This may be especially important for 6-11 year-old boys with ASD who engage in significantly less physical activity than their peers in the general population.
            Cover page: Physical activity rates in children and adolescents with autism spectrum disorder compared to the general population.
            • Article
            • Peer Reviewed
            UC Irvine Previously Published Works (2009)
            Cortico-limbic brain activity associated with anger may be susceptible to nicotine and, thus, may contribute to smoking initiation and nicotine addiction. The purpose of the study was to identify the brain regions that are most reactive to nicotine and show the greatest association with anger task performance. Twenty adult nonsmokers (9 women, 11 men) participated in two laboratory sessions to assess brain metabolism with fluoro deoxy-glucose Positron Emission Topography (FDG-PET) in response to nicotine and placebo patches during an anger provocation task. Outcome variables for the anger provocation task were reaction time, intensity and length of retaliation. Reaction time was associated with nicotine-induced changes in the left thalamus. Length of retaliation was associated with a functionally linked set of cortical and subcortical structures such as right frontal lobe, right anterior cingulate (BA 24), right uncus, left parietal lobe, left BA 11, left cingulate, left BA 25, left amygdala, left BA 30, left BA 38 and BA 9. These findings reveal the underlying brain circuitry targeted by nicotine during anger provocation.
            • 1 supplemental ZIP
            Cover page: Nicotine-induced brain metabolism associated with anger provocationCreative Commons 'BY' version 4.0 license
            • Article
            • Peer Reviewed
            UC Irvine Previously Published Works (2015)
            The aim of the study was to examine functional brain activity in response to unpleasant images in individuals with the 7-repeat (7R) allele compared to individuals with the 4-repeat (4R) allele of the dopamine receptor D4 (DRD4) gene (VNTR in exon 3). Based on the response ready hypothesis, individuals with the DRD4-4R/7R genotype were expected to show greater functional brain activity in response to unpleasant compared to neutral stimuli in specific regions of the frontal, temporal, parietal and limbic lobes, which form the networks involved in attentional, emotional, and preparatory responses. Functional Magnetic Resonance Imaging activity was studied in 26 young adults (13 with the DRD4-4R/7R genotype and 13 with the DRD4-4R/4R genotype). Participants were asked to look at and subjectively rate unpleasant and neutral images. Results showed increased brain activity in response to unpleasant images compared to neutral images in the right temporal lobe in participants with the DRD4-4R/7R genotype versus participants with the DRD4-4R/4R genotype. The increase in right temporal lobe activity in individuals with DRD4-4R/7R suggests greater involvement in processing negative emotional stimuli. Intriguingly, no differences were found between the two genotypes in the subjective ratings of the images. The findings corroborate the response ready hypothesis, which suggests that individuals with the 7R allele are more responsive to negative emotional stimuli compared to individuals with the 4R allele of the DRD4 gene.
              Cover page: Increased brain activity to unpleasant stimuli in individuals with the 7R allele of the DRD4 geneCreative Commons 'BY' version 4.0 license
              Top