Mental health discrimination has been reported to have been experienced by 50–90% of individuals with mental health disorders (Corker et al. 2013; Corrigan et al. 2003), and has been associated with a variety of negative outcomes, including impaired functioning, unemployment and reduced health service use. However, despite the prevalence of ADHD in the adult population (~2.5–5%) (Fayyad et al. 2007), to date, there has been little research into the relationship between ADHD and mental health discrimination. This study aimed to address this knowledge gap by examining the association between ADHD symptoms and perceived mental health discrimination in the English adult population.
Data were obtained from the Adult Psychiatric Morbidity Survey (n=7403), undertaken between October 2006 and December 2007 by the National Centre for Social Research and the University of Leicester, UK. Multistage stratified probability sampling was used to obtain a nationally representative sample of the adult population of England (aged ≥16 years) living in private households, with responses obtained from 7461 of the 13,171 households identified as eligible. Survey respondents received a £5–10 gift voucher in return for their time.
Computer-assisted self-interviews (CASI)* were used to collect information on perceived mental health discrimination (dependent variable) in the previous 12 months. Information on respondents’ ADHD symptoms (independent variable) in the previous 6 months was obtained using the ADHD Self-Report Scale (ASRS),† with respondents’ scores initially divided into four strata (0–9; 10–13; 14–17; 18–24) and then dichotomised, with those respondents who had a score ≥14 considered as having ADHD symptoms. Chi-squared and student’s t-tests were used to calculate the differences in sample characteristics by experience of mental health discrimination, and the prevalence, as a percentage, of mental health discrimination across the four ADHD strata was determined. A multivariable logistic regression analysis then assessed the association between ADHD symptoms (i.e. ASRS score ≥14) and mental health discrimination, with a hierarchical analysis involving the sequential inclusion of different sets of variables performed to determine the extent to which the different covariates included in the analysis affect this association. Covariates included several sociodemographic indicators, stressful life events, alcohol dependence in the past 6 months, drug use in the past year, and presence of physical health conditions and common mental disorders.‡
A total of 7274 adults, aged 18–95 years (mean [standard deviation (SD)] age, 47.5 [18.2] years; female, 51.6%), were included in the analytic sample. Of these, 5.4% were determined to have ADHD symptoms, and 1.1% had experienced mental health discrimination. Overall, 8.1% of respondents with ADHD symptoms (ASRS score ≥14) reported experience of mental health discrimination in the past year, compared with 0.7% of those without ADHD symptoms. Additionally, the prevalence of perceived discrimination increased as the level of ADHD symptoms increased: among those with the lowest level of ADHD symptoms (ASRS score of 0–9), mental health discrimination was reported by only 0.3% of individuals, whereas the prevalence was 2.3% in those with a score of 10–13, and 5.2% in those scoring 14–17. Among respondents with the most severe ADHD symptoms (ASRS score 18–24), there was a statistically significant increase (demonstrated by non-overlapping confidence intervals [CIs]) in the prevalence of perceived mental health discrimination in the past 12 months (18.8%; 95% CI 11.0–30.3%), compared with individuals with lower ASRS scores. The results of the fully adjusted multivariable analysis demonstrated that the presence of ADHD symptoms (ASRS score ≥14) was associated with an almost 3-times-higher odds of experiencing mental health discrimination (odds ratio [OR] 2.81; 95% CI 1.49–5.31), even after adjusting for all potentially confounding variables.
This study had several limitations. First, information on experience of mental health discrimination was collected via a single “yes” or “no” question, meaning that the details of the discrimination were unclear. Second, the low survey response rate (57%) may indicate that individuals with ADHD symptoms and/or more experience of mental health discrimination are less willing to participate in such surveys, which may have affected the results. Additionally, due to its sensitive nature, mental health discrimination may have been under-reported in the survey, although the authors noted that the use of CASI may have addressed this limitation to some extent. Furthermore, this study focused on ADHD symptoms, rather than ADHD diagnoses, making it feasible that the symptoms being measured may have been due to comorbid psychiatric disorders, rather than solely due to ADHD, although it should be noted that common mental disorders were controlled for in the multivariable analysis.
The authors concluded that adults with ADHD symptoms are significantly more likely to experience mental health discrimination than those without ADHD symptoms, and suggested that, since discrimination has been linked with negative consequences in individuals with mental health disorders, it may be an important factor in the negative outcomes associated with adult ADHD. The authors highlighted that ADHD is under-diagnosed and under-treated in the adult population, and suggested that interventions to increase knowledge and understanding of ADHD among the general public may be required to reduce the discrimination and stigma associated with ADHD in adults.
*Previous research has suggested that computer-assisted self-interviews are linked with a greater willingness of respondents to divulge information considered to be ‘sensitive’, such as mental health discrimination. In the current study, respondents were asked “Have you been unfairly treated in the last 12 months, that is since (date), because of your mental health?”. Answer options were “yes” and “no”
†The ADHD Self-Report Scale is a 6-item scale that assessed the frequency of inattention (4 items) and hyperactivity (2 items) symptoms over the past 6 months using a 5-point response scale from 0 (“never”) to 4 (“very often”), providing an overall score of 0–24. Higher scores indicate greater symptom severity
‡Sociodemographic indicators included in the analysis were: sex, age, ethnicity (white British or other), educational qualification (degree, non-degree, A-level, GCSE, other), marital status and income (high, ≥£29,826; middle, £14,057–£29,826; low, <£14,057). Stressful life events were assessed via a question that asked about 18 negative events across respondents’ life course (e.g. experience of being bullied, expulsion from school, death of a family member), with the number of events experienced summed to give a score ranging from 0–18. The Alcohol Use Disorders Identification Test and the Severity of Alcohol Dependence Questionnaire were used to assess alcohol dependence, with a score ≥4 indicating alcohol dependence. Drug use was determined by asking respondents if they had consumed any of a range of illicit drugs in the past 12 months. Respondents were also asked if they had received a professional diagnosis of any of 20 health conditions in the past year, and the Clinical Interview Schedule Revised was used to determine International Statistical Classification of Diseases and Related Health Problems, 10th Revision (ICD-10) diagnoses of common mental disorders in the past week
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