Dual-process models of attention-deficit/hyperactivity disorder (ADHD) suggest that both executive functioning and regulatory functions (e.g., processing speed) are involved and that executive function weaknesses may be associated specifically with symptoms of inattention-disorganization but not hyperactivity-impulsivity. Adults aged 18-37 (105 with ADHD, 90 controls) completed a neuropsychological battery. The ADHD group had weaker performance than did the control group (p<.01) on both executive and speed measures. Symptoms of inattention-disorganization were uniquely related to executive functioning with hyperactivity-impulsivity controlled. Inattention was associated with slower response speed, and hyperactivity-impulsivity with faster output speed. Results were not accounted for by IQ, age, gender, education level, or comorbid disorders. Findings are discussed in terms of developmental and dual-process models of ADHD leading into adulthood.

We review different conceptions of inhibitory control that may be relevant to the regulatory problems featured in borderline personality disorder~BPD!. These conceptions have often been framed with regard to personality traits of inhibitory control, but can also be related to cognitive measures of response suppression as well as affect regulation. Reactive behavioral inhibition is relatively unstudied in relation to BPD. A substantial amount of literature links executive function problems with BPD, but that literature has not isolated executive response inhibition nor been controlled for other personality disorder symptoms of antisociality, attention-deficit0hyperactivity disorder ADHD!, or depression, anxiety, or posttraumatic symptoms. We therefore conducted a study of this question looking at BPD symptoms in an adult sample with a small number of BPD subjects and other disorders. Results indicated that symptoms of BPD were correlated with response inhibition~measured by stop signal reaction time! even after controlling for the overlap of stop inhibition with ADHD, antisociality, and other Axis II disorder symptoms. We conclude by hypothesizing discrete developmental routes to BPD, based on different mechanism breakdowns, which would be amenable to empirical investigation at the cognitive or trait level of analysis.

Attention-deficit/hyperactivity disorder (ADHD) is associated with impairments in occupational, social, and educational functioning in adults. This study examined relations of adaptive impairment to ADHD symptom domains (inattentive-disorganized and hyperactive-impulsive) and to deficits in executive functioning (EF) in 195 well-characterized adults (105 ADHD, 90 non-ADHD, between ages 18 and 37). Participants completed a battery of EF measures as well as assessments of adaptive functioning. Confirmatory factor analyses were used to validate latent factors for adaptive functioning and EF. In a measurement model, weaker EF was associated with poorer adaptive functioning (r = -.30). When multi-informant composite variables for current inattentive-disorganized and hyperactive-impulsive ADHD symptoms were included in the structural model, EF no longer predicted adaptive functioning. While both symptom composites were similarly related to EF (inattentive-disorganized r = .36; hyperactive-impulsive r = .29), inattentive-disorganized symptoms accounted for more variance in adaptive functioning (67.2% vs. 3.6%). Furthermore, for retrospectively reported childhood symptoms of ADHD, only the inattentive-disorganized symptom domain was related to EF or adaptive impairment. These results suggest that, in adults with ADHD, inattentive-disorganized symptoms may be the primary contributor to key aspects of poorer adaptive function and may be the behavioral path through which EF deficits lead to adaptive impairment.

Objective Interest continues in neuropsychological measures as cross-disorder intermediate phenotypes in understanding psychopathology. A central question concerns their specificity versus generalizability to particular forms of psychopathology, particularly for executive functioning (EF) and response speed. Three conceptual models examining these relationships were tested to clarify this picture at different levels in the diagnostic hierarchy. Method Participants (total n = 641, age 18–60) yielded complete structured diagnostic interviews and a neuropsychological test battery comprising measures of executive function, processing speed, and IQ. Repeated measures MANOVA, linear regression, and structural equation modeling (SEM) were used to test (1) a Specificity model, which proposes that individual disorders are associated with component EF processes and Speed; (2) a Severity model, which proposes that the total number of comorbid disorders explain poor EF and/or slow Speed; and (3) a Dimensional model, which proposes that internalizing versus externalizing disorders are differentially related to EF or Speed. Results EF effects were best explained by a Specificity model, with distinct aspects of EF related to ADHD versus antisocial substance use disorders. Speed, on the other hand, emerged as a general indicator of externalizing psychopathology in the Dimensional model, as well as overall severity of psychopathology in the Severity Model. Conclusions Granular approaches are likely to be most productive for linking EF to psychopathology, whereas response speed has underutilized potential as an endophenotype for psychopathology liability. Results are discussed in terms of an integrated conceptualization of neuropsychological processes and putative neural systems involved in general and specific aspects of psychopathology.

Objectives: Previous studies have found a season of birth effect for women with eating disorders. However, findings regarding the two types of season of birth (i.e. month of birth and temperature at conception) have been conflicting, and few studies have examined relationships between season of birth and general disordered eating in non-clinical populations. The present study sought to examine this relationship more closely by investigating both month of birth and temperature at conception in undergraduate women. Method: Subjects included 427 undergraduate females from a large university in the United States. Disordered eating in the areas of body dissatisfaction, compensatory behaviour, binge eating and weight preoccupation was assessed with the Minnesota Eating Behaviors Survey (MEBS). Results: No significant mean differences in MEBS scores were found between those individuals born in the first versus second half of the year. Furthermore, no significant associations were found between disordered eating and temperature at conception. Discussion: Our findings suggest that disordered eating symptoms do not show a season of birth effect. Discrepancies between these findings and those for clinical samples suggest the possible presence of different aetiological mechanisms for general eating symptoms versus clinical eating disorders.