Zachary W. Adams

Permanent URI for this collection

https://hdl.handle.net/1805/43730

Browse

Now showing 1 - 10 of 80

Inhibitory Functioning across ADHD Subtypes: Recent Findings, Clinical Implications and Future Directions
(Wiley, 2008) Adams, Zachary W.; Derefinko, Karen J.; Milich, Richard; Fillmore, Mark T.; Psychiatry, School of Medicine
Although growing consensus supports the role of deficient behavioral inhibition as a central feature of the combined subtype of ADHD (ADHD/C; Barkley, 2007; Nigg, 2001), little research has focused on how this finding generalizes to the primarily inattentive subtype (ADHD/I). This question holds particular relevance in light of recent work suggesting that ADHD/I might be better characterized as a disorder separate from ADHD/C (Diamond, 2005; Milich et al., 2001). The current paper describes major findings in the area of inhibitory performance in ADHD and highlights recent research suggesting important areas of divergence between the subtypes. In particular, preliminary findings point to potential differences between the subtypes with respect to how children process important contextual information from the environment, such as preparatory cues that precede responses and rewarding or punishing feedback following behavior. These suggestive findings are discussed in the context of treatment implications, which could involve differential intervention approaches for each subtype targeted to the specific deficit profiles that characterize each group of children. Future research avenues aimed toward building a sound theoretical model of ADHD/I and a better understanding of its relation to ADHD/C are also presented. Specifically, investigators are encouraged to continue studying the complex interplay between inhibitory and attentional processes, as this area seems particularly promising in its ability to improve our understanding of the potentially distinct pathologies underlying the ADHD subtypes.
Examining Manual and Visual Response Inhibition among ADHD Subtypes
(Springer, 2010) Adams, Zachary W.; Fillmore, Mark T.; Psychiatry, School of Medicine
This study compared inhibitory functioning among ADHD subtype groups on manual and visual versions of the stop task. Seventy-six children, identified as ADHD/I (n=17), ADHD/C (n=43), and comparison (n=20) completed both tasks. Results indicated that both ADHD groups were slower to inhibit responses than the comparison group on both tasks. Comparison children were faster to inhibit than activate responses on both tasks. Children in the ADHD groups also demonstrated this robust pattern on the manual task. However, on the visual task, the ADHD groups evidenced slowed inhibition comparable to the time required to activate responding. This implies that the visual task is more sensitive than the manual task to inhibitory deficits associated with ADHD. The ADHD/I and the ADHD/C groups did not differ on most measures, suggesting that neither stop task is effective in differentiating the subtypes. These findings extend work highlighting the role of disinhibition in ADHD, and contrast recent work suggesting divergence between ADHD subtypes.
Does Response Variability Predict Distractibility among Adults with Attention-Deficit/Hyperactivity Disorder?
(American Psychological Association, 2011) Adams, Zachary W.; Roberts, Walter M.; Milich, Richard; Fillmore, Mark T.; Psychiatry, School of Medicine
Increased intra-individual variability in response time (RTSD) has been observed reliably in ADHD and is often used as a measure of inattention. RTSD is assumed to reflect attentional lapses and distractibility, though evidence for the validity of this connection is lacking. We assessed whether RTSD is an indicator of inattention by comparing RTSD on the stop-signal task (SST) to performance on the Delayed Oculomotor Response (DOR) Task, a measure of distractibility. Participants included 30 adults with ADHD and 28 controls. Participants completed the SST and the DOR task, which measured subjects’ ability to maintain attention and avoid distraction by inhibiting reflexive saccades toward distractors. On the SST, the ADHD group was slower to inhibit than controls, indicating poorer inhibitory control in ADHD. The ADHD group also displayed slower RTs, greater RTSD, and more omission errors. On the DOR task, the ADHD group displayed more premature saccades (i.e., greater distractibility) than controls. Greater variability in RT was associated with increased distraction on the DOR task but only in ADHD participants. Results suggest that RTSD is linked to distractibility among adults with ADHD and support the use of RTSD as a valid measure of inattention in ADHD.
Drinking Motives as Mediators of the Impulsivity-Substance Use Relation: Pathways for Negative Urgency, Lack of Premeditation, and Sensation Seeking
(Elsevier, 2012) Adams, Zachary W.; Kaiser, Alison J.; Lynam, Donald R.; Charnigo, Richard J.; Milich, Richard; Psychiatry, School of Medicine
Trait impulsivity is a reliable, robust predictor of risky, problematic alcohol use. Mounting evidence supports a multidimensional model of impulsivity, whereby several distinct traits serve as personality pathways to rash action. Different impulsivity-related traits may predispose individuals to drink for different reasons (e.g., to enhance pleasure, to cope with distress) and these different motives may, in turn, influence drinking behavior. Previous findings support such a mediational model for two well-studied traits: sensation seeking and lack of premeditation. This study addresses other impulsivity-related traits, including negative urgency. College students (N = 432) completed questionnaires assessing personality, drinking motives, and multiple indicators of problematic drinking. Negative urgency, sensation seeking, and lack of premeditation were all significantly related to problematic drinking. When drinking motives were included in the model, direct effects for sensation seeking and lack of premeditation remained significant, and indirect effects of sensation seeking and lack of premeditation on problematic drinking were observed through enhancement motives. A distinct pathway was observed for negative urgency. Negative urgency bore a significant total effect on problematic drinking through both coping and enhancement motives. This study highlights unique motivational pathways through which different impulsive traits may operate, suggesting that interventions aimed at preventing or reducing problematic drinking should be tailored to individuals' personalities. For instance, individuals high in negative urgency may benefit from learning healthier strategies for coping with distress.
Interactive effects of drinking history and impulsivity on college drinking
(Elsevier, 2013) Adams, Zachary W.; Milich, Richard; Lynam, Donald R.; Charnigo, Richard J.; Psychiatry, School of Medicine
The transition from adolescence into emerging adulthood is a critical developmental period for changes in alcohol use and drinking related problems. Prior research has identified a number of distinct developmental alcohol use trajectories, which appear to be differentially related to young adult drinking outcomes. Another correlate of alcohol use in early adulthood is impulsivity. The primary aim of this study was to examine the moderating role of impulsivity in the relation between patterns of past alcohol use and hazardous drinking during the first year of college. Participants (N=452; 49% male; mean age 18.5years; 82% Caucasian) completed self-report measures during the first year of college, including retrospective alcohol use calendars, current alcohol use and drinking problems, and personality. Group-based trajectory modeling was used to identify groups with similar adolescent drinking history from retrospective, self-report. Four groups were identified: abstainers/very light users, late/moderate users, early/moderate users, and steep increase/heavy users. The abstainer/very light user group reported the lowest levels of alcohol use and problematic drinking in college; the steep increase/heavy use group reported the highest levels of alcohol use and problematic drinking. As predicted, the role of personality-specifically urgency, or emotion-based rash action-was strongest among moderate use groups. These findings may be helpful in guiding targeted prevention and intervention programs for alcohol use and abuse.
Psychiatric Problems and Trauma Exposure in Non-detained Delinquent and Non-delinquent Adolescents
(Taylor & Francis, 2013) Adams, Zachary W.; McCart, Michael R.; Zajac, Kristyn; Danielson, Carla Kmett; Sawyer, Genelle K.; Saunders, Benjamin E.; Kilpatrick, Dean G.; Psychiatry, School of Medicine
Objective: This study examined the prevalence of and associations between specific psychiatric disorders, substance use problems, and trauma exposure in a sample of delinquent and non-delinquent adolescents. Method: A nationally representative sample of adolescents (n = 3,614; mean age = 14.5 years, SD = 1.7; 51% male; 71% White, non-Hispanic, 13.3% African American, non-Hispanic, 10.7% Hispanic) was interviewed via telephone about engagement in delinquent acts and their experience of posttraumatic stress disorder, major depressive episode, substance use, interpersonal violence, and other forms of trauma exposure. Results: Delinquent adolescents were more likely than non-delinquent adolescents to experience trauma; they were also more likely to report past-year posttraumatic stress disorder, major depressive episode, alcohol abuse, and non-experimental drug use. After accounting for the effects of demographics and trauma exposure, delinquency was associated with increased likelihood of posttraumatic stress disorder and problematic substance use in both genders and increased likelihood of major depressive episode in girls. Conclusions: Findings highlight substantial overlap among delinquency, trauma exposure, posttraumatic stress disorder, and major depressive episode in adolescents and the need for interventions that address these varied clinical problems. Future work should examine the factors underlying the development of these relations over time.
Prevalence and predictors of PTSD and depression among adolescent victims of the Spring 2011 tornado outbreak
(Wiley, 2014) Adams, Zachary W.; Sumner, Jennifer A.; Danielson, Carla Kmett; McCauley, Jenna L.; Resnick, Heidi S.; Grös, Kirstin; Paul, Lisa A.; Welsh, Kyleen E.; Ruggiero, Kenneth J.; Psychiatry, School of Medicine
Background: Relatively few studies have examined prevalence and predictors of posttraumatic stress disorder (PTSD) or major depressive episode (MDE) in disaster-affected adolescents. Fewer still have administered diagnostic measures or studied samples exposed to tornadoes, a common type of disaster. Further, methodologic problems limit the generalizability of previous findings. This study addressed prevalence estimates and risk factors for PTSD and MDE among adolescents exposed to the Spring 2011 tornado outbreak in Alabama and Joplin, Missouri. Methods: A large (N = 2000), population-based sample of adolescents and caregivers, recruited randomly from tornado-affected communities, participated in structured telephone interviews. PTSD and MDE prevalence were estimated for the overall sample, by gender, and by age. Hierarchical logistic regression was used to identify risk factors for PTSD and MDE. Results: Overall, 6.7% of adolescents met diagnostic criteria for PTSD and 7.5% of adolescents met diagnostic criteria for MDE since the tornado. Girls were significantly more likely than boys to meet diagnostic criteria for MDE, and older adolescents were more likely than younger adolescents to report MDE since the tornado. Female gender, prior trauma exposure, and an injured family member were associated with greater risk for PTSD and MDE. Specific incident characteristics (loss of services, concern about others' safety) were associated with greater PTSD risk; prior disaster exposure was associated with lower MDE risk. Conclusions: However, most adolescents were resilient following tornado exposure, roughly 1 in 15 developed PTSD, 1 in 13 developed MDE, and many more endorsed subclinical mental health problems. Information regarding specific risk factors can guide early screening, prevention, and intervention efforts in disaster-affected communities.
Epidemiology of Traumatic Experiences in Childhood
(Elsevier, 2014) Saunders, Benjamin E.; Adams, Zachary W.; Psychiatry, School of Medicine
The epidemiology of traumatic experiences in childhood is a key context for research, clinical treatment, program management, and policy development. This article discusses the conceptual, methodological, and programmatic challenges in precisely answering even relatively simple questions concerning the basic prevalence and incidence of important trauma types among American youth. Findings from studies using nationally representative samples and directly interviewing youth about their trauma histories are reviewed, and lifetime prevalence rates for various types of traumatic experience presented. Clinical application of this information and future directions are discussed.
Elucidating Dimensions of Posttraumatic Stress Symptoms and their Functional Correlates in Disaster-Exposed Adolescents
(Elsevier, 2014) Sumner, Jennifer A.; Pietrzak, Robert H.; Danielson, Carla Kmett; Adams, Zachary W.; Ruggiero, Kenneth J.; Psychiatry, School of Medicine
The aim of this study was to elucidate the dimensional structure of posttraumatic stress disorder (PTSD) and potential moderators and functional correlates of this structure in disaster-affected adolescents. A population-based sample of 2000 adolescents aged 12-17 years (M = 14.5 years; 51% female) completed interviews on post-tornado PTSD symptoms, substance use, and parent-adolescent conflict between 4 and 13 months (M = 8.8, SD = 2.6) after tornado exposure. Confirmatory factor analyses revealed that all models fit well but a 5-factor dysphoric arousal model provided a statistically significantly better representation of adolescent PTSD symptoms compared to 4-factor dysphoria and emotional numbing models. There was evidence of measurement invariance of the dysphoric arousal model across gender and age, although girls and older adolescents aged 15-17 years had higher mean scores than boys and younger adolescents aged 12-14 years, respectively, on some PTSD dimensions. Differential magnitudes of association between PTSD symptom dimensions and functional correlates were observed, with emotional numbing symptoms most strongly positively associated with problematic substance use since the tornado, and dysphoric arousal symptoms most strongly positively associated with parent-adolescent conflict; both correlations were significantly larger than the corresponding correlations with anxious arousal. Taken together, these results suggest that the dimensional structure of tornado-related PTSD symptomatology in adolescents is optimally characterized by five separate clusters of re-experiencing, avoidance, numbing, dysphoric arousal, and anxious arousal symptoms, which showed unique associations with functional correlates. Findings emphasize that PTSD in disaster-exposed adolescents is not best conceptualized as a homogenous construct and highlight potential differential targets for post-disaster assessment and intervention.
Identifying the facets of impulsivity that explain the relation between ADHD symptoms and substance use in a nonclinical sample
(Elsevier, 2014) Roberts, Walter; Peters, Jessica R.; Adams, Zachary W.; Lynam, Donald R.; Milich, Richard; Psychiatry, School of Medicine
Adults with attention-deficit/hyperactivity disorder (ADHD) are at higher risk to use substances than their nonclinical peers. Increased levels of impulsivity are generally thought to contribute to their increased levels of risk. Impulsivity is a multifaceted construct, however, and little research to date has attempted to identify which facets of impulsivity contribute to the increased rates of substance abuse among individuals with ADHD. The current study examined the relation among ADHD symptom clusters (i.e., hyperactivity/impulsivity and inattention), substance use rates (i.e., alcohol use, nicotine use, and marijuana use), and personality processes associated with impulsive behavior in a group of young adults. Participants were 361 undergraduate students. Both symptom clusters were positively associated with rates of substance use. Specifically, hyperactive/impulsive symptoms were associated with alcohol and nicotine use, and inattentive symptoms were associated with alcohol use. Several pathways from hyperactive/impulsive symptoms to alcohol, nicotine, and marijuana use via specific facets of impulsivity were identified. These findings have implications for understanding the relation between ADHD symptoms and substance use, as well as clinical implications for preventing and treating substance use problems in individuals with symptoms of ADHD.

Browse

Browsing Zachary W. Adams by Issue Date

Results Per Page

Sort Options