ADHD and bipolar disorder (BD) share common symptomatology such as mood instability, distractibility, impulsivity, restlessness and irritability. Additionally, both are chronic disorders with lifelong impairment and strong familial and genetic links. ADHD and BD can co-occur, and it is easy for one diagnosis to be overlooked or misdiagnosed; therefore, patients diagnosed with ADHD should be screened for BD and vice versa. However, there are uncertainties about the relationship between ADHD and BD; therefore, this study aimed to provide a report on the co-occurrence of ADHD and BD in adults.
Data from adults with a diagnosis of BD (type I [BD-I] or type II [BD-II]) according to the Diagnostic and Statistical Manual of Mental Disorders – 4th Edition – Text Revision (DSM-IV-TR), who were treated at the Lucio Bini Mood Disorder Centres in Rome and Cagliari, Italy in the past 15 years, were included in this study. Each individual was assessed using a variety of rating scales,* including the Adult ADHD Self-Report Scale v1.1 (ASRS-v1.1), which was used to assess ADHD. Information on academic failures and school dropouts was also collected for this study.
A total of 703 individuals with BD (54.9% female; mean age 46.0 [95% confidence interval (CI) 44.8–47.1] years) were included in the study. The mean age of BD onset was 26.3 (95% CI 25.4–27.2) years and the average illness duration was 19.7 (95% CI 18.6–20.7) years. A lifetime diagnosis of ADHD was present in 24.6% (n=173) of individuals with BD (male/female prevalence ratio = 2.35). In this study, no individual had ever received psychostimulant treatment.
The analyses compared individuals with BD and ADHD with those with BD but without ADHD:
- ADHD was associated with BD-I more than BD-II (59.0 [95% CI 51.2–66.4] versus 41.0 [95% CI 33.6–48.8]). A history of ADHD in BD was linked to a higher ASRS-v1.1 score for inattention in individuals with ADHD compared with those without (11.5 [95% CI 10.6–12.6] versus 10.1 [95% CI 9.5–10.7; p=0.01]), but this was not significant for impulsivity (20.8 [95% CI 17.0–24.6] versus 19.8 [95% CI 18.8–20.8; p=0.32).
- Individuals with BD and ADHD were found to have more school dropouts (1.14 [95% CI 0.96–1.32] versus 0.29 [95% CI 0.23–0.35]; p<0.0001) and were less likely to be educated beyond high school compared with those with BD but without ADHD (19.1 [95% CI 13.5–25.7] versus 3.96 [95% CI 2.47–5.99]; p<0.0001).
- Unemployment (20.2 [14.5–27.0] versus 11.1 [8.58–14.1]; p=0.002) and separation and divorce (32.4 [25.5–39.9] versus 19.6 [16.3–23.3]; p=0.0005) were more likely to be associated with individuals with BD and ADHD compared with those with only BD. In addition, high socioeconomic status was more common in individuals with BD but without comorbid ADHD compared with those with BD and ADHD (29.8 [2.53–33.9] versus 18.5 [13.0–25.1]; p=0.0004).
- Compared with individuals with BD only, a family history of psychiatric illness (79.1 [75.3–82.4] versus 69.4 [61.9–76.1]; p=0.009), mood disorder (74.2 [70.2–77.8] versus 59.5 [51.8–66.9]; p=0.0003), BD (38.3 [34.1–42.6] versus 29.5 [22.8–36.9]; p=0.04) or suicide (10.9 [8.42–13.9] versus 4.62 [2.02–8.9]; p=0.01) was less likely to be associated with BD and ADHD.
- Individuals with BD and ADHD were at a significantly higher risk for suicidal acts (p=0.008; but not suicidal ideation or acts [p=0.24]) and substance use (including alcohol [p=0.0001] and cigarettes [p=0.0006], but not caffeine [p=0.06]) and were significantly more likely to meet diagnostic criteria for other psychiatric comorbidities (p=0.02) compared with those with BD without ADHD.
- Individuals with BD and ADHD also exhibited more [hypo]mania (1.17 [0.69–1.65] versus 0.70 [0.50–0.90]; p=0.02), and were found to be more irritable (2.49 [2.18–2.78] versus 1.62 [1.46–1.78]; p<0.0001) than those with only BD.
The authors acknowledged limitations of the study, as this was retrospective, and the precise timing of onset of ADHD relative to the start of BD was unknown. Additionally, using the Conners’ Adult ADHD Diagnostic Interview for DSM-IV may have provided more detailed information about the diagnosis of ADHD.
In concluding, the authors reported a prevalence of ADHD of a quarter of adults diagnosed with BD, with a higher prevalence associated with BD-I. In addition, the co-occurrence of ADHD and BD was associated with several unfavourable outcomes, as well as more [hypo]mania than those diagnosed with BD only.
Read more about outcomes for adults with bipolar disorder and ADHD here
*Individuals were assessed using the following rating scales and questionnaires: ASRS-v1.1; Hamilton Depression Rating Scale; Hamilton Anxiety Rating Scale; Young Mania Rating Scale; Mood Disorder Questionnaire; and the Italian short version of the Temperament Evaluation of Memphis Pisa, Paris and San Diego self-report questionnaire
Pinna M, Visioli C, Rago CM, et al. Attention deficit-hyperactivity disorder in adult bipolar disorder patients. J Affect Disord 2018; 243: 391-396.