Psychopathology in Williams Syndrome 1 Running Head: PSYCHOPATHOLOGY IN WILLIAMS SYNDROME Psychopathology in Williams syndrome: the effect of individual differences across the lifespan

The present research aimed to comprehensively explo re sychopathology in Williams syndrome (WS) across the lifespan and evaluate the relationship between psychopathology and age category (child or adult), gender and cognitive ability. The parents of 50 participants with WS, aged 6-50 years , were interviewed using the Schedule for Affective Disorders and Schizophrenia for School-Age Children (KSADS-PL). The prevalence of a wide range of Axis I DSM-IV disorders was assessed. In addition to high rates of anxiety and Attention Deficit Hyperactivity Disorder (ADHD) (38% and 20% respectively), 14% of our sample met criteria for a depressive disorder and 42% of participants were no t experiencing any significant psychopathological difficulties. There was some evi d nce for different patterns of psychopathology between children and adults with WS and between males and females. These relationships were largely in keepin g with those found in the typically developing population, thus supporting the validity of applying theory and treatment approaches for psychopathology in the typically dev eloping population to WS. Psychopathology in Williams Syndrome 3 Psychopathology in Williams syndrome: Similarities and individual differences across the lifespan Williams Syndrome (WS) is a genetic disorder charac terised by a microdeletion of a sequence of genes on chromosome 7 including the gene for Elastin (ELN; Ewart et al., 1993). Cases occur sporadically and affect both genders equally. Prevalence is estimated to be around 1 in 20,000 (M artin, Snodgrass, & Cohen, 1984), however a higher rate of 1 in 7,500 has been report d (Stromme, Bjornstad, & Ramstad, 2002). Although there is some phenotypic h eterogeneity (Mervis, Morris, Bertrand, & Robinson, 1999; Porter & Coltheart, 200 5), the deletion typically results in dysmorphic facial features and short stature, me dical problems such as supravalvular aortic stenosis, a mild to moderate i nt llectual delay and high levels of anxiety and attention problems. Only a small body of work has explored psychopathol ogy in large cohorts of WS individuals. The most consistently reported psyc hopathological findings support early descriptions of increased rates of hyperactiv ity, attention problems, anxiety and phobias in the WS population (Von Armin & Engel, 19 64), when compared to intellectually impaired control groups (Dykens, 200 3; Einfeld, Tonge, & Florio, 1997; Udwin, 1990). The present research aims to explore the prevalence of a wide range of psychopathology in children and adults with WS, usi ng a diagnostic interview measure, and to explore the relationship between ps ychopathology and three individual difference variables in WS: age category (childhood vs adulthood), gender and cognitive ability. The majority of research exploring psychopathology in WS has used behavioural questionnaires or checklists. These met hods provide an efficient means of gathering data on large groups of subjects and have made a significant contribution to Psychopathology in Williams Syndrome 4 understanding of emotional and behavioural difficul ties in WS. The utility of these measures is, however, constrained by a number of li mitations and more recent research has utilised interview measures validated gainst the Diagnostic and Statistical Manual of Mental Disorders (DSM-IV; Ame rican Psychiatric Association, 1994). These recent research findings have extended knowle dge by demonstrating that individuals with WS not only experience high r ates of anxiety and attention problems, but also increased rates of a number of c linical diagnoses. For example, Dykens (2003) conducted a detailed investigation of anxiety and fears in individuals with WS using the anxiety disorders section of the Diagnostic Interview for Children and Adolescents (DICA-R; Reich, 2000). The results indicated that 18% of the participants with WS presented with Generalised Anx iety Disorder (GAD) and 35% presented with Specific Phobia. Dykens (2003) furth er noted that 16% of WS participants met criteria for more than one anxiety disorder and highlighted the need for research assessing the comorbidity of anxiety a nd other psychiatric disorders. The most thorough investigation of psychopathology in WS to date (Leyfer, Woodruff-Borden, Klein-Tasman, Fricke, & Mervis, 20 06) utilised the Anxiety Disorders Interview Schedule (ADIS-IV; Silverman & Albano, 1996). Participants were aged between 4 and 16 years. The results suppo rted previous findings of high rates of anxiety; 53.8% of the sample met criteria for a current diagnosis of Specific Phobia and 11.8% met criteria for a current diagnos is f GAD. Chavira, Stein, Bailey & Stein (2004) used the ADIS-IV to assess the preva lence of anxiety disorders in a large cohort of typically developing children and f ound that 3% met criteria for GAD and 10% met criteria for Specific Phobia. In compar ing these prevalence rates to those Psychopathology in Williams Syndrome 5 reported by Leyfer et al. (2006) it is apparent tha individuals with WS may be at increased risk for these two anxiety disorders. In addition to the high rates of anxiety disorders, Leyfer et al. (2006) also found that 64.7% of their sample met criteria for A DHD. Of those with ADHD, the majority met criteria for the Inattentive subtype. With regards to comorbidity, Leyfer et al. (2006) reported that half of their WS cohort met criteria for more than one diagnosis. In keeping with patterns of comorbidity found in the typically developing population, ADHD and Specific Phobia commonly co-oc curred. The research discussed has made an important contri bution to the literature on psychopathology in WS by highlighting specific area s of risk. The findings further indicate that there is extensive heterogeneity with in WS in terms of psychopathology; it is clear that not all individuals with WS meet d iagnostic criteria for ADHD, GAD or Specific Phobia. Despite the progress made by rece nt research, there are a number of important limitations that need to be addressed: th ere as been no thorough examination of Axis I DSM-IV diagnoses in both chil dren and adults with WS, as a result of this, research relating to diagnoses that are more common in adults such as psychosis and depression is severely lacking and de scriptions of comorbidity are consequently limited. The present research aims to address these limitations whilst also exploring the relationship between psychopatho logy and three individual difference variables: age category (childhood vs ad ulthood), gender and cognitive ability. Individual differences variables and psychopatholog y There are a number of advantages to using diagnosti c interviews validated against DSM-IV to assess psychopathology in WS. In particular, categorising symptoms according to DSM-IV diagnoses provides an opportunity to apply the Psychopathology in Williams Syndrome 6 extensive knowledge that is associated with these d iagnoses in typically developing individuals, to the WS population. However, Karmilo ff-Smith (1998) highlights that although the behaviour of individuals with neurodev elopmental disorders may appear to be the same as that observed in typically develo ping individuals, it cannot be assumed that the underlying causes or processing me chanisms are also the same; similar end-states are possible via highly divergen t developmental trajectories. Following this reasoning, before applying theory an d treatment approaches based on work with typically-developing individuals to the W S population, we must first examine whether the causes and processes associated w th the diagnoses are comparable in both populations. The present researc h aims to address this issue by examining associations between specific DSM-IV diag noses and individual difference variables in WS and comparing these relationships w th those reported for the typically-developing population. Further to this, e xamining these associations may also indicate possible sources of heterogeneity wit hin the presentation of psychopathology in WS. The relationships between DS M-IV diagnoses and age category, gender and cognitive ability in the typic ally-developing population and in WS, will now be discussed.