Zachary W. Adams

Response Style Differences in the Inattentive and Combined Subtypes of Attention-Deficit/Hyperactivity Disorder

This study examined potential differences between the inattentive and combined ADHD subtypes using laboratory tasks assessing behavioral inhibitory processes. Seventy-five children completed two tasks of behavioral inhibition believed to isolate different processes: the cued reaction time task (CRT), a basic inhibition task, and the go/no-go task (GNG), a complex inhibition task that incorporates motivational contingencies. Three groups of participants were identified, including ADHD/Inattentive (n = 17), ADHD/Combined (n = 37), and comparison (n = 21). Results indicated that rather than showing behavioral inhibition deficits, the ADHD/I children appeared overly inhibited, as evidenced by slower reaction times across the two tasks and significantly higher errors of omission in the GNG task. Additionally, the ADHD/I children did not demonstrate cue dependency effects on the CRT task, suggesting that they were failing to incorporate relevant information before making a response. The sluggish and inhibited performance of the ADHD/I group challenges the idea that it is a subtype of ADHD.

Inhibitory Functioning Across ADHD Subtypes: Recent Findings, Clinical Implications, and Future Directions

Although growing consensus supports the role of deficient behavioral inhibition as a central feature of the combined subtype of ADHD (ADHD/C; Barkley 1997 Psychol Bull 121:65-94; Nigg 2001 Psychol Bull 127:571-598), 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 Dev Psychopathol 17:807-825; Milich et al. 2001 Clin Psychol Sci Pract 8:463-488). This article 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.

Identifying the facets of impulsivity that explain the relation between ADHD symptoms and substance use in a nonclinical sample

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.

Epidemiology of Traumatic Experiences in Childhood

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.

Psychiatric Problems and Trauma Exposure in Nondetained Delinquent and Nondelinquent Adolescents

This study examined the prevalence of and associations between specific psychiatric disorders, substance use problems, and trauma exposure in a sample of delinquent and nondelinquent adolescents. A nationally representative sample of adolescents (n = 3,614; M 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. Delinquent adolescents were more likely than nondelinquent adolescents to experience trauma; they were also more likely to report past-year posttraumatic stress disorder, major depressive episode, alcohol abuse, and nonexperimental 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. 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.

Ethical Challenges in the Treatment of Individuals With Intellectual Disabilities

The effective provision of psychotherapy services to individuals with intellectual disability requires consideration of ethical issues related to clinical competence, access to services, obligations to multiple parties, guardianship, and appropriate assessment practices. This article provides an overview of major ethical considerations with guidance for clarifying and resolving common ethical concerns. Psychologists are encouraged to expand access to psychotherapy services for this population while maintaining awareness of potential modifications, training needs, and boundaries of professional competence. The authors provide recommendations and resources for effective and ethical treatment of psychotherapy clients with intellectual disabilities.

Specific dimensions of impulsivity are differentially associated with daily and non-daily cigarette smoking in young adults.

Young adults are at risk for initiation of tobacco use and progression to tobacco dependence. Not every person who smokes cigarettes becomes tobacco dependent, however, and non-daily smoking is becoming more prevalent among those who use tobacco. It is likely that individual differences in psychosocial and behavioral factors influence risk for engaging in non-daily and daily cigarette smoking. The objective of this study was to investigate the associations between impulsivity and smoking status in young adults who vary in frequency of cigarette smoking. Young adult first-year college students between the ages of 18-24 (512) were classified to one of three groups: non-smokers, non-daily smokers, or daily smokers, and impulsivity was assessed using the UPPS-P (negative and positive urgency, lack of premeditation, lack of perseverance, sensation seeking). When all impulsivity dimensions were used simultaneously to predict smoking status, negative urgency predicted increased risk of membership in the daily smoking group and lack of premeditation predicted increased risk of membership in the non-daily smoking group. These results suggest that dimensions of impulsivity may contribute differentially to forms of smoking behavior in young adults.

Elucidating dimensions of posttraumatic stress symptoms and their functional correlates in disaster-exposed adolescents

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.

Comorbidity of PTSD, Major Depression, and Substance Use Disorder Among Adolescent Victims of the Spring 2011 Tornadoes in Alabama and Joplin, Missouri

Objective: The purpose of this study was twofold: (1) to estimate the prevalence of comorbid posttraumatic stress disorder (PTSD), major depressive episode (MDE), and substance use disorder (SUD); and (2) to identify risk factors for patterns of comorbidity among adolescents affected by disasters. Method: A population-based sample of 2,000 adolescents (51% female; 71% Caucasian, 26% African American) aged 12 to 17 years (M = 14.5, SD = 1.7) and their parents was recruited from communities affected by the spring 2011 tornadoes in Alabama and Joplin, Missouri. Participants completed structured telephone interviews assessing demographic characteristics, impact of disaster, prior trauma history, Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition (DSM-IV), symptoms of posttraumatic stress disorder (PTSD) and major depressive episode (MDE), and substance use disorder (SUD) symptoms. Prevalence estimates were calculated for PTSD + MDE, PTSD + SUD, MDE + SUD, and PTSD + MDE + SUD. Hierarchical logistic regression was used to identify risk factors for each comorbidity profile. Results: Overall prevalence since the tornado was 3.7% for PTSD + MDE, 1.1% for PTSD + SUD, 1.0% for MDE + SUD, and 0.7% for PTSD + MDE + SUD. Girls were significantly more likely than boys to meet criteria for PTSD + MDE and MDE + SUD (ps < .05). Female gender, exposure to prior traumatic events, and persistent loss of services were significant risk factors for patterns of comorbidity. Parental injury was associated with elevated risk for PTSD + MDE. Adolescents should be evaluated for comorbid problems, including SUD, following disasters so that appropriate referrals to evidence-based treatments can be made. Conclusions: Results suggest that screening procedures to identify adolescents at risk for comorbid disorders should assess demographic characteristics (gender), impact of the disaster on the family, and adolescents’ prior history of stressful events.

Examining manual and visual response inhibition among ADHD subtypes.

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.