Longitudinal studies of children with Attention-deficit/Hyperactivity Disorder (ADHD) demonstrate that the disorder frequently persists into adulthood (1
) and is associated with significant life-long functional impairment (5
). Different sampling methods as well as age at follow-up result in varying rates of persistence, but longitudinal studies suggest persistence rates range from 4% to more than 80% (1
). A recent epidemiological study found that nearly 40% of individuals with childhood ADHD have persisting symptoms significant enough for diagnosis in adulthood (7
). Thus, among many people, ADHD may be conceptualized as a chronic disorder that is not confined to childhood and adolescence.
As is the case with childhood ADHD, adult ADHD carries with it an increased risk for comorbid Axis I psychopathology (8
). Among adults with ADHD, several studies have indicated elevated rates of comorbid mood (6
), anxiety (13
), and substance use (15
) disorders. In addition, adults with ADHD are oftentimes characterized by affective volatility (17
), occupational instability (19
), poor social relationships (17
), and impulsive and self-destructive behaviors (7
) that may or may not be related to the presence of ADHD or other Axis I disorders. As such, investigators (22
) have recently begun to explore the degree to which Axis II Personality Disorders might account for some of the functional impairment associated with ADHD in adults.
According to the Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition Text Revision (27
), personality disorders are enduring, pervasive behavioral and thinking patterns that are inflexible and maladaptive. Rather than reflecting transient mental or emotional states that may be more indicative of Axis I disorders, personality disorders are characterized by stable attributes of personality that cause distress or impairment in multiple environments. Cluster A disorders are characterized by odd or eccentric behaviors and include Paranoid, Schizoid, and Schizotypal Personality Disorders. Cluster B disorders include Antisocial, Borderline, Histrionic, and Narcissistic Personality Disorders, with behaviors that are dramatic or emotional. Avoidant, Dependent, and Obsessive-Compulsive Personality Disorders comprise Cluster C with behaviors that are anxious or fearful in nature.
Numerous studies have shown an association between childhood ADHD and adult antisocial personality disorder (28
), but only a limited number have examined associations between childhood ADHD and other adult personality disorders. Although the link between ADHD and personality disorders may be phenomenological (i.e., overlapping diagnostic criteria), the disorders may co-occur because of common neurobiological and/or environmental risk factors including dysregulation in the hypothalamic-pituitary-adrenal axis (32
), adverse early experiences with fear or anger (33
), temperament (34
) or some combination of these factors. A recent longitudinal study indicated that young adults with a history of ADHD are more likely than those without such history to have a personality disorder, particularly Antisocial, Histrionic, or Borderline personality disorders (22
). Consistent with this, individuals with a retrospectively documented history of disruptive behavior disorders during childhood, including ADHD, were significantly more likely to have Cluster B personality disorders in general, and Borderline Personality Disorder in particular, when compared to individuals with childhood internalizing disorders (26
Retrospective studies also suggest a link between childhood disruptive behavior disorders, and non-Cluster B disorders. Lewinsohn and colleagues reported that adults with retrospectively-reported disruptive behavior disorders experienced higher rates of Antisocial, Histrionic, Narcissistic, Schizoid, and Schizotypal personality disorders than those not reporting a history of ADHD behaviors (24
). Additionally, childhood ADHD without comorbid Axis I psychopathology may also increase risk for particular personality disorders. Adults with a history of pure ADHD have greater rates of Antisocial, Histrionic, Narcissistic, and Borderline personality disorders compared with those with a history of comorbid ADHD and internalizing symptomatology (25
). Consistent with this, nearly 90% of a sample of adults with personality disorders reported clinically significant ADHD symptoms in childhood (23
Taken together, these results suggest an association between childhood ADHD and later personality disorder. However, there are a number of limitations inherent to these studies. All but two of the studies (22
) linking ADHD with Axis II symptomatology other than Antisocial personality disorder have relied on retrospective reporting by clinically-referred adults to make the diagnosis of childhood ADHD. Yet, reliance on retrospective assessment of childhood status in a clinical sample is problematic because of the questionable validity of childhood diagnosis (3
). Additionally, there may be other confounding variables. For example, in several of the studies of adults with personality disorders, there was either no clear control group (25
) or the control group was poorly matched to the psychiatric group on key demographic characteristics, including sex, age, and comorbid diagnoses (23
). Finally, it is unclear from these studies whether adult personality disorders are linked to a history of childhood ADHD per se, without regard to adult outcomes, or to the persistence of ADHD into adulthood.
The primary goal of the present study was to assess, as compared to controls, personality disorders in a longitudinal sample of late adolescents who were diagnosed with ADHD during childhood. A secondary aim was to determine the degree to which personality disorder diagnoses are linked to the persistence of ADHD symptoms into adulthood as opposed to the childhood condition per se. It was hypothesized that as compared to matched controls, youth previously diagnosed with ADHD would have elevated levels of Cluster B, but not Clusters A or C personality disorders, and that increased rates of personality disorder would be associated primarily with the persistence of ADHD into adolescence.