Attention-deficit/hyperactivity disorder and autism spectrum disorders in adult psychiatric patients

Abstract

Background: Knowledge about attention-deficit/hyperactivity disorder (ADHD) and autism spectrum disorders (ASD) in adult psychiatry is scant. Aims: Estimate prevalence, psychiatric morbidity patterns and impact of ADHD/ASD diagnoses in general adult psychiatry services. Material and methods: Two adult psychiatric out-patient groups were screened and clinically examined for ADHD and ASD. A new screening instrument, the Autism Spectrum Disorders in Adults Screening Questionnaire (ASDASQ) was developed for ASD. The Wender Utah Rating Scale was used for retrospective screening of childhood ADHD symptoms. A new questionnaire was used in an attempt to measure the subjective impact of receiving an ADHD or ASD diagnosis in adulthood in a group of consecutively clinically evaluated adult patients and their significant others. A very large data-set of all registered psychiatric patients at one clinic over a 20-year-period was used to assess time trends in clinical diagnoses of ADHD and ASD and “comorbidities”/psychiatric service use. Results: Of screened adult psychiatric patients 1.4% had ASD and most of these were treated at a centre for chronic disorders. The rate of ASD in this centre was 3.2%. A quarter of the patients with ASD had previous diagnoses of schizophrenia. The ASDASQ showed good psychometric properties. The rate of ADHD in the screened group of general psychiatric out-patients was 21.9%. These patients had been variably diagnosed, often with affective disorder. Greater subjective impact of the diagnosis for patients with ADHD than ASD was suggested. Perceived positive post-diagnosis change was reported by patients and significant others, and as regards medication (ADHD), housing and habilitation service contact (ASD). The rate of ADHD diagnoses increased from 1990 to 2009, but only about 2.7% of the whole adult psychiatric patient group received this diagnosis. ASD diagnosis rates also went up but only to about 1.3% of all registered patients. Discussion: In adult psychiatry, many patients have ADHD or ASD, developmental disorders that underlie or are overshadowed by “psychiatric illness”. Some patients seek help for problems related to the formerly unrecognized ADHD or ASD rather than for “psychiatric disorder”. ADHD seems to be much more common than ASD, and in both disorders concomitant psychiatric illness is usually present. It is important not to rely only on self-assessment questionnaires for diagnosis. An essential part of diagnostic work-up is a detailed history taking and testing of cognitive and adaptive development/capacity, currently not standard in adult psychiatric practice. Measuring the subjective impact of ADHD or ASD diagnoses proved to be difficult. The rate of diagnosed ADHD/ASD in adult psychiatry went up over the past two decades but was, by 2010, far below the likely “real” rate. The underdiagnosis of ADHD/ASD in adult psychiatry remains a huge clinical problem. Key words: Attention-Deficit/Hyperactivity Disorder (ADHD), Autism Spectrum Disorder (ASD), adults, psychiatry, Autism Spectrum Disorder in Adults Screening Questionnaire (ASDASQ)