eliminated AS as a separate diagnosis in 2013, and folded it into the umbrella of autism spectrum disorders. Other sets of diagnostic criteria have been proposed by Szatmari et al. and by Gillberg and Gillberg. Diagnosis is most commonly made between the ages of four and eleven. A comprehensive assessment involves a multidisciplinary team that observes across multiple settings, and includes neurological and genetic assessment as well as tests for cognition, psychomotor function, verbal and nonverbal strengths and weaknesses, style of learning, and skills for independent living. The "gold standard" in diagnosing ASDs combines clinical judgment with the Autism Diagnostic Interview-Revised (ADI-R), a semistructured parent interview; and the Autism Diagnostic Observation Schedule (ADOS), a conversation and play-based interview with the child. Delayed or mistaken diagnosis can be traumatic for individuals and families; for example, misdiagnosis can lead to medications that worsen behavior. Underdiagnosis and overdiagnosis may be problems. The cost and difficulty of screening and assessment can delay diagnosis. Conversely, the increasing popularity of drug treatment options and the expansion of benefits has motivated providers to overdiagnose ASD. There are indications AS has been diagnosed more frequently in recent years, partly as a residual diagnosis for children of normal intelligence who are not autistic but have social difficulties. There are questions about the external validity of the AS diagnosis. That is, it is unclear whether there is a practical benefit in distinguishing AS from HFA or PDD-NOS; different screening tools may render different diagnoses for the same person. Differential diagnosis Many children with AS are initially misdiagnosed with attention deficit hyperactivity disorder (ADHD). Diagnosing adults is more challenging, as standard diagnostic criteria are designed for children and the expression of AS changes with age. Adult diagnosis requires painstaking clinical examination and thorough medical history gained from both the individual and other people who know the person, focusing on childhood behavior. Conditions that must be considered in a differential diagnosis along with ADHD include other ASDs, the schizophrenia spectrum, personality disorders, obsessive–compulsive disorder, major depressive disorder, semantic pragmatic disorder, nonverbal learning disorder, social anxiety disorder, Tourette syndrome, stereotypic movement disorder, bipolar disorder, social-cognitive deficits due to brain damage from alcohol use disorder, and obsessive–compulsive personality disorder (OCPD). Screening Parents of children with Asperger syndrome can typically trace differences in their children's development to as early as 30 months of age. Developmental screening during a routine check-up by a general practitioner or