Psychiatric comorbidities in women with cardiometabolic conditions with and without ADHD: a population-based study

Attention-deficit/hyperactivity disorder (ADHD) is an impairing neurodevelopmental disorder with prevalence of around 3–4% in adults [1, 2]. The persistence of ADHD symptoms from childhood to adulthood is substantial and around two thirds of children with ADHD have been estimated to have continued functional impairments as adults [3, 4]. Psychiatric comorbidities are common in ADHD, where people with ADHD have a decreased life expectancy and more than double the risk of premature death compared with individuals without ADHD [5, 6]. There is increasing recognition of a gender difference in symptoms and comorbidities in ADHD, but until recently, studies have primarily focused on male symptomatology [7, 8]. Internalizing symptoms of ADHD are more common in women than men, including higher prevalence of mood and anxiety comorbidities [9, 10]. Studies on adolescents also indicate higher risk of self-harm in females with ADHD compared to males, as well as compared to other females without ADHD [11, 12], but further research is needed. Moreover, both ADHD and self-harm are associated with suicide attempts, placing females with ADHD at risk of attempted or completed suicide [13‐15]. However, further research on the female symptomatology of ADHD is needed [7].

Although much less studied than mood and anxiety disorders, emerging evidence suggests substantial comorbidity between adult ADHD and chronic conditions such as obesity, type 2 diabetes, hypertension, hyperlipidemia, and cardiovascular diseases [10, 16‐21]. If not identified and treated, these conditions—hereafter termed cardiometabolic conditions—can lead to a considerable health burden, societal costs, and premature mortality [22, 23]. Systematic reviews, meta-analyses, and cohort studies [24‐26] have demonstrated positive associations of cardiometabolic conditions with a range of psychiatric disorders, including mood, anxiety, and stress-related disorders. Comorbid psychiatric disorders have been shown to be associated with increased mortality rates in people suffering from cardiometabolic conditions [27]. In these studies, associations appear to be even more distinct among women than men [24, 25]. Furthermore, cardiometabolic conditions have been found to be associated with suicide ideation and suicide attempts, especially among those suffering from comorbid depression [28, 29]. Co-occurring cardiometabolic conditions and psychiatric disorders increase the risk of premature death, highlighting the importance of appropriate management of these common, chronic conditions.

Comorbidity between ADHD and cardiometabolic conditions can be traced to both genetic factors and certain lifestyle-related risk factors, e.g., abnormal eating patterns, physical inactivity, sleep disruption, and high alcohol and nicotine use, all of which are common among adults with ADHD [30‐34]. However, current understanding of underlying mechanisms and consequences of co-occurring ADHD and cardiometabolic conditions is limited, especially in females.

Leveraging a large nationwide study of Icelandic women, we aimed to narrow the evidence gap around female ADHD and cardiometabolic comorbidity by determining the prevalence of obesity, hypertension, type 2 diabetes, and cardiovascular diseases among women with ADHD. To enhance our understanding of mental health among women with cardiometabolic conditions and co-occurring ADHD, we examined associations with anxiety and mood disorders, alcoholism and substance use disorder (SUD), self-harm, and suicide attempts.

Among a total of 26,668 women, 2299 (8.6%) reported having an ADHD diagnosis (mean age 36.7 years, SD 12.5 years) and 10,957 (41.1%) reported any cardiometabolic condition (mean age of 47.6 years, SD 12.9 years). A total of 978 (3.7%) women reported having both ADHD and one or more cardiometabolic condition (mean age 39.6 years, SD 12.5 years).

Compared with those without ADHD, women with an ADHD diagnosis were younger (36.7 years vs. 44.9 years), more likely to be single (33.6% vs. 23.0%), more likely not to have children (30.3% vs. 18.1%), less likely to have finished higher education, i.e., university and university higher education (35.9% vs. 56.3%), more likely to have low or low-medium income (47.0% vs. 27.9%), and more likely to be inactive from work (retired/disability/sick leave) (23.9% vs. 14.3%)―particularly because of a disability (22.4% vs. 8.8% on disability benefits). They were also more likely to smoke (25.6% vs. 14.3%), use other nicotine (27.6% vs. 12.4%), and binge drink monthly or more often (19.2% vs. 13.2%) (Table 1).

This nationwide population-based study on women with co-occurring ADHD and cardiometabolic conditions and their association with anxiety and mood disorders, alcoholism and substance use disorder (SUD), self-harm, and suicide attempts generated two main findings. First, cardiometabolic conditions, including obesity, hypertension, type 2 diabetes, and myocardial infarctions, were more prevalent in women with a diagnosis of ADHD than in those without. Second, women with cardiometabolic conditions and co-occurring ADHD had a 2- to 5-fold higher risk of all measured history of psychiatric diagnoses compared with women with cardiometabolic conditions without ADHD.

These findings align with emerging evidence showing an association between ADHD and cardiometabolic conditions [10, 17, 19]. The PRs of type 2 diabetes and myocardial infarctions were substantially higher in women with ADHD compared to those without ADHD (2.08 and 2.53, respectively). This was especially evident in the youngest age group (18–30 years) suggesting that women with ADHD may develop serious cardiometabolic conditions at an earlier age than those without ADHD. In line with previous findings [41, 42], our results show higher prevalence of lifestyle-related risk factors associated with cardiometabolic conditions among women with ADHD, including smoking and binge drinking, as well as lower education, emphasizing the need for preventive strategies, i.e., diagnosing ADHD early and providing educational support for girls and women with ADHD. The findings also have importance for clinicians treating women with ADHD. Clinicians need to be vigilant of cardiometabolic risk factors and the high risk of serious cardiometabolic conditions in women with ADHD. Findings have indicated that ADHD medication treatment may diminish the risk of some negative health behaviors and thereby lower the risk of poor somatic health outcomes [43], but further research is needed. ADHD medication can increase heart rate and blood pressure, raising concerns about their cardiovascular safety. However, a recent meta-analysis showed no significant association between ADHD medication and cardiovascular diseases across age-groups, though a modest increase in risk could not be ruled out [44].

Our findings indicate that women with cardiometabolic conditions and co-occurring ADHD have a notably elevated prevalence of poor mental health outcomes, e.g., increased anxiety and depressive symptoms. Poor mental health has been linked to worse outcomes in cardiovascular diseases [27]. The high prevalence rate of depressive symptoms is alarming with nearly two thirds of the women with ADHD and cardiometabolic conditions reporting moderate/severe depressive symptoms. Moreover, roughly half of these women have PTSD symptoms above the threshold score, and nearly half of them have moderate/severe anxiety symptoms. Studies have indicated that ADHD medication could reduce the risk of developing depression [45] emphasizing the importance of clinical management of ADHD. In our data, women with co-occurring ADHD and cardiometabolic conditions clearly had an elevated prevalence of psychiatric multimorbidity and history of self-harm and suicide attempts, putting them at risk for severely impaired quality of life and premature death. Clinicians treating women with cardiometabolic conditions and co-occurring ADHD need to be aware of the risk of poor mental health outcomes in this population and the potential impacts on disease management and prognosis. This patient group will benefit from a multi-disciplinary approach, incorporating psychiatrists, psychologists, and cardiologists.

A strength of this study is a relatively large sample size that is representative of the female adult population in Iceland regarding demographic characteristics. Yet, there are several limitations to be noted. First, this is a cross-sectional study, and we have no information on how or when the psychiatric disorders or cardiometabolic disorders were diagnosed. However, as ADHD typically arises early in development, it precedes the onset of most physical health conditions and mood and anxiety disorders [46, 47]. Second, as the SAGA Cohort Study is a study on trauma history, it could be that women who had experienced trauma were more likely to participate in the study than women who had not. These women could be more likely to suffer from psychiatric disorders than other women. For example, 8.6% of the women in our study reported a diagnosis of ADHD, which is higher than the reported prevalence of ADHD among female adults in the general population [2]. Third, diagnoses of cardiometabolic conditions, ADHD, and psychiatric disorders are self-reported which could lead to misclassification of the reported diagnoses; it is difficult to infer the implications of this for our findings as diagnoses can both be underreported and overreported. As we rely on information on history of diagnoses, only women who have been diagnosed with ADHD were included in the analyses, i.e., women with undiagnosed ADHD were not included in the analyses. The measured associations between ADHD and cardiometabolic conditions, and the association with psychiatric disorders might therefore be underestimated in the results as one could assume that women with undiagnosed ADHD are also at increased risk of cardiometabolic and psychiatric comorbidities. In future studies, it would be interesting to examine the same associations stratified by sex and age. Furthermore, it would be interesting to examine the role of lifestyle-related factors associated with ADHD on the development of cardiometabolic conditions and, in turn, the prognosis of psychiatric disorders. It would have important clinical implications to understand if providing behavioral support or treatment for relevant changes in lifestyle could hinder the development of these disorders. Finally, it would be interesting to examine the role of ADHD medication on the development of cardiometabolic conditions and psychiatric comorbidities to understand if medication could act as a protective factor or possibly as a risk factor for this association.

Our findings highlight the role of ADHD in cardiometabolic conditions and associated psychiatric comorbidities. Our findings indicate that women with ADHD could develop these conditions at an earlier age than other women. Furthermore, women suffering from cardiometabolic conditions and co-occurring ADHD have increased prevalence of both mood and anxiety disorders as well as having a diagnosis of alcoholism or substance use disorder. Moreover, they are at an increased risk of self-harm and suicide attempts. Clinicians, in the field of psychiatry, cardiology, and endocrinology, need to be watchful of the psychiatric and cardiometabolic problems that commonly affect adult women with ADHD to increase their well-being and quality of life and to decrease the risk of early death. These findings also stress the importance of diagnosing women with ADHD early. Treating their symptoms and providing educational and behavioral support could reduce the likelihood of them developing cardiometabolic conditions and psychiatric disorders, by diminishing the impact of lifestyle-related risk factors for cardiometabolic conditions that are often associated with ADHD.