Accurate differential diagnosis and a greater appreciation of the social difficulties associated with Asperger syndrome are critical because the high proportion of individuals who may be overlooked, misdiagnosed with another psychiatric condition, or present with comorbid psychiatric disorders such as depression and anxiety. Although there is a wealth of information regarding children with autism spectrum disorders, little is known about the identification of adults on the higher end of the autism spectrum. While there is no single set of criteria or “gold standard” for making a late diagnosis of Asperger syndrome in adults, there are a limited number of instruments that can be used for screening and assessment. The following phenotypic screening instruments are useful for adults who may have Asperger syndrome.
• The Autism Spectrum Disorder in Adults Screening Questionnaire (ASDASQ; Nylander & Gillberg, 2001).
• The Asperger Syndrome (and high-functioning autism) Diagnostic Interview (ASDI; Gillberg, Gillberg, Restam, & Wentz, 2001).
• The Autism-Spectrum Quotient (AQ; Baron-Cohen, Wheelwright, Skinner, Martin, and Clubley, 2001).
• The Empathy Quotient (EQ; Baron-Cohen & Wheelwright, 2004).
Although these screening measures can be useful in the identification process, they cannot substitute for a diagnostic assessment and validation of the symptomatology identified by these instruments. We now have a diagnostic assessment specifically designed for adults. The Adult Asperger Assessment (AAA; Baron-Cohen, Wheelwright, Robinson, & Woodbury-Smith, 2005) is a relatively new semi-structured interview schedule developed for the late diagnosis of Asperger syndrome in adulthood. It links the above referenced AQ and EQ screening instruments, and uses more stringent diagnostic criteria specifically related to adults. These criteria include all the symptoms from the DSM-IV as well as several other criteria based on the characteristics of Asperger syndrome in adults. The AAA employs a template in which the individual is asked to endorse items from the AQ and EQ to provide examples of symptoms. During the clinical interview, the clinician validates these symptom examples by gathering information from both the individual and his or her relative or other informant. Following the interview, the clinician then formulates a diagnostic impression based on confirmation of the symptoms and prerequisites of the Asperger syndrome criteria.
Little is known about the prognosis and outcomes in adults with Asperger syndrome in that there are relatively few long-term follow-up studies available. However, it does seem clear that outcome can depend greatly on the degree of support provided in adulthood. Although early adulthood may bring about symptom reduction and improved functioning, individuals with Asperger syndrome continue to have a need for services. As the knowledge and awareness of Asperger syndrome increases, many adults are expected to recognize their symptomatology, even though they may have not experienced major social difficulties and clinical impairment earlier in life. This late recognition and disclosure will result in a greater need for services as individuals seek treatment to address the secondary problems associated with the condition. A diagnosis in adulthood can also lead to greater self-understanding, self-advocacy, and better decision-making in life span activities such as employment and personal relationships.
Gaus, V.L. (2007). Cognitive-behavioral therapy for adult Asperger syndrome. New York: Guilford.