Although the recognition and treatment of adult ADHD has recently improved in several European countries, underdiagnosis remains a problem due to a high rate of psychiatric comorbidities. The aim of this study was to establish the prevalence of undiagnosed adult ADHD in university psychiatric clinics providing inpatient and outpatient care in the Czech Republic and Hungary.
Eligible study participants included males and females (aged 18–60 years) who were undergoing inpatient or outpatient treatment for a Diagnostic and Statistical Manual of Mental Disorders – 4th Edition – Text Revision (DSM-IV-TR) Axis I diagnosis other than ADHD.* The study consisted of two phases:
- Phase I – Screening Phase: participants completed the screening version of the Adult ADHD Self-Report Scale (ASRS). All positively screened subjects and approximately half of the negatively screened subjects were invited to further participate in the study.
- Phase II – Interview Phase: participants completed a series of clinical interviews to gather data on demographic and clinical characteristics, as well as to assess for the presence of ADHD (DSM-IV-TR symptom list†/Conners’ Adult ADHD Rating Scale [CAARS]‡) and other potential psychiatric disorders (MINI-PLUS 5.0 structured interview§).
Based on the clinical interview, the study investigators assessed whether the participant met the criteria for the clinical diagnosis of adult ADHD. Modified diagnostic criteria were also applied to investigate the effect of diagnostic criteria on the prevalence estimates; these included three modified criteria based on their relation to the DSM-IV-TR criteria, and a fourth criterion based on DSM-5TM criteria:
- ADHD DSM-IV-TR diagnostic group: based on the full set of DSM-IV-TR criteria for both childhood and adult ADHD (combined, or inattentive, or hyperactive-impulsive type), with supporting information based on the clinical interview.
- ADHD no-onset group: based on DSM-IV-TR criteria for both childhood and adult ADHD (combined, or inattentive, or hyperactive-impulsive type) without the criterion of onset.
- ADHD symptoms only group: based on DSM-IV-TR criteria (6/9 symptoms of either inattentive or hyperactivity-impulsivity, or both) for childhood and adult ADHD.
- ADHD DSM-5TM diagnostic group: based on the full set of DSM-5TM criteria for both childhood and adult ADHD, with supporting information from the clinical interview. The study protocol was written prior to the publication of DSM-5TM. DSM-5TM criteria were added to the protocol after its publication.
Among 708 psychiatric in- and outpatients,¥ estimated point prevalences of adult ADHD were as follows:
- ADHD DSM-IV-TR diagnostic group: 6.99 (95% confidence interval [CI] 5.11–8.86)
- ADHD no-onset group: 9.18 (95% CI 7.06–11.31)
- ADHD symptoms only group: 13.41 (95% CI 10.90–15.92)
- ADHD DSM-5TM diagnostic group: 9.27 (95% CI 7.13–11.40).
Results also demonstrated that current suicide risk was significantly associated with the presence of undiagnosed adult ADHD (p = 0.02); however, depression (p = 0.93), alcohol dependence (p = 0.94) substance dependence (p = 0.88), anorexia (p = 0.25), and anxiety- and stress-related disorders (agoraphobia, generalised anxiety disorder, obsessive-compulsive disorder, panic disorder, post-traumatic stress disorder and social phobia; p = 0.41) were not.
This study was limited by its cross-sectional design, which did not allow the determination of causal relationships. Furthermore, no data were collected to characterise the severity of comorbid disorders. Despite this, the authors stated that these findings highlight a need for further educational efforts to improve the recognition and treatment of ADHD in adults, particularly in those with comorbid substance-use and other mental disorders.
*Study exclusion criteria included a history of major neurological disorders and diagnosis of the following psychiatric disorders: schizophrenia and cognitive disorders (e.g., dementia)
†A structured clinical interview was earlier developed by the authors (Bitter et al. 2010), using the symptom list of ADHD in the DSM-IV-TR, including function impairment and onset criteria (i.e., whether the symptoms caused problems before 7 years of age). The interview comprised two sections to assess for the presence of ADHD in childhood and adulthood, respectively
‡The CAARS 66 item self-report version (CAARS-S:L) included four factor-derived subscales (inattentive/memory problems, hyperactivity/restlessness, impulsivity/emotional lability, problems with self-concept) and three DSM-IV-TR ADHD subscales (DSM-IV-TR Inattentive Symptoms, DSM-IV-TR Hyperactive-Impulsive Symptoms, DSM-IV-TR Total ADHD Symptoms), the ADHD Index and the Inconsistency Index. Items were rated on a 4-point scale (0–3)
§The validated Czech and Hungarian versions of the MINI-PLUS structured interview were applied for the assessment of lifetime and current DSM-IV-TR Axis psychiatric disorders
¥716 patients were included in the screening phase (Budapest: 580; Prague: 136) between 7 July 2012 and 26 June 2014. Eight patients were excluded
Bitter I, Simon V, Bálint S, et al. How do different diagnostic criteria, age and gender affect the prevalence of attention deficit hyperactivity disorder in adults? An epidemiological study in a Hungarian community sample. Eur Arch Psychiatry Clin Neurosci 2010; 260: 287-296.
Bitter I, Mohr P, Balogh L, et al. ADHD: a hidden comorbidity in adult psychiatric patients. Atten Defic Hyperact Disord 2019; 11: 83-89.