Abstract

Background
Cyclothymia seems to be often associated with coexisting ADHD symptoms, although this comorbidity is understudied. Emotional dysregulation is a core symptom of both conditions.

Methods
Adult subjects with cyclothymia were consecutively enrolled at the outpatient service of the Second Psychiatry Unit of the Pisa University Hospital (Italy). Screening for ADHD was performed using the Adult ADHD Self-Report Scale (ASRS). We analyzed differences in sociodemographic and clinical characteristics between subjects with and without ADHD symptomatology.

Results
Of the total sample of 107 subjects, 43 % screened positive for ADHD. ADHD+ subjects were significantly younger than ADHD- subjects, had a lower level of education, a higher prevalence of psychiatric comorbidity, and a more frequent family history for ADHD and alcohol use disorder. In addition, ADHD+ subjects scored higher than ADHD- subjects on the affective instability, negative emotionality, and emotional impulsivity subscales of the RIPoSt-40 questionnaire, as well as on the 40‐item version of Reactivity, Intensity, Polarity, and Stability questionnaire (RIPoSt-40) total score. They also showed a stronger association with the cyclothymic and depressive subscales of the Temperament Evaluation of Memphis, Pisa, Paris, and San Diego (TEMPS-M) scale.

Limitations
the small sample size, the cross-sectional nature of the study, the use of self-report questionnaires, and the use of a screening test to assess comorbidity with ADHD symptomatology.

Conclusions
ADHD symptomatology is very common in cyclothymic individuals, and emotional dysregulation blurs the diagnostic boundaries between the two disorders. Several clinical features suggest the need for systematic evaluation of ADHD in patients with cyclothymic disorder.

Introduction

In the DSM-5, cyclothymic disorder belongs to the bipolar spectrum of mood disorders and is defined by the presence of at least 2 years of both hypomanic and depressive periods that never meet the criteria for a full-blown affective episode (American Psychiatric Association, 2013). Although cyclothymia is considered a very common psychiatric disorder, comprehensive epidemiologic data are lacking. In clinical samples, it occurs more frequently in women than in men, and the incidence ranges from 0.4 % to 13 %, depending on the criteria used (Van Meter et al., 2012).

The way of current diagnostic classifications to describe cyclothymia only in terms of alternating depressive and hypomanic symptoms in an attenuated form completely neglects psychological aspects, behavioral symptoms, and important clinical features such as excessive mood reactivity, impulsivity, and anxiety, leading to a limited understanding of the disorder and, consequently, its underdiagnosis.

Actually, the core features of cyclothymia are emotional dysregulation (ED), i.e., rapid oscillations of intense affect with a difficulty in regulating these oscillations or their behavioral consequences, and marked mood reactivity, whether in terms of intensity and duration. Indeed, as early as adolescence, cyclothymic individuals report a stable trait of exaggerated sensitivity to both positive or negative external stimuli of psychological, environmental, chemical, and physical nature (Perugi et al., 2015). Mood reactivity and instability are invariably associated with a number of psychological and behavioral consequences that may be the main complaints or symptoms for many of these individuals.

Conclusions

Future studies are needed to explore the relationships between cyclothymia and ADHD in clinical samples. ED is a key feature of both syndromes, which often blurs the diagnostic boundaries between the two disorders and facilitates misdiagnosis. It is useful for clinicians to identify the elements that, when present in the individual with cyclothymia, suggest the need for further evaluation for ADHD. ADHD+ patients appear to represent a subpopulation characterized by higher rates of familiarity with ADHD, earlier onset of affective disorders, higher rates of comorbidity with other psychiatric disorders, significantly higher ED burden, poorer course of illness, and greater functional impairment. Obesity and uncontrolled eating disorders may be additional factors indicating comorbid ADHD symptomatology. Finally, cyclothymic individuals with ADHD exhibit predominantly negative emotionality and appear to lack the type of positive emotionality which is typical of patients with ADHD without comorbid cyclothymia (Christiansen et al., 2019).