Comorbidity between ADHD and bipolar Disorder

The aims of the review
Comorbidity between ADHD and Bipolar Disorder (BD) is associated with greater severity of BD.
The current study aims at investigating in a specialized mood disorders clinic, the percentage of comorbid ADHD-BD subjects and assessing the impact of ADHD on the severity of BD.

ADHD has been reported to be frequently comorbid with BD. ADHD is found in 6 % and 15% of female and male sufferers of BD, respectively, and rates higher than 20% have even been reported in some studies. Epidemiological studies have moreover shown that BD is found in approximately 20% of subjects suffering from ADHD. Several hypotheses have been raised to explain this higherthan-chance association ranging from overlapping dimensions to shared genetic vulnerability.

Comorbidity between ADHD and BD has been associated with early-life onset of BD, with higher numbers of depressive and mixed episodes, with fewer asymptomatic periodes, with worse outcomes and with poor response to treatment. In addition, subjects suffering from the two disorders show higher rates of psychiatric comordidities, such as anxiety and substance use disorders.

The medical records of subjects who were clinically assessed for mood disorders (major depressive disorder and BD) between January 2010 and December 2013, in a specialized outpatient center for the treatment and care of subjects suffering from mood disorders, were analyzed by a trained psychologist. During this period 539 subjects were referred to the mood disorder outpatient clinic
and underwent an extensive clinical evaluation with, among others, semi-structured and self-report questionnaires. The diagnosis of BD is mainly made upon a careful clinical assesment based on ICD-10 and DSM criteria for the disorder usually involving more than one senior psychiatrist.

In addition, for patients diagnosed with BD, the medical notes were carefully checked for any mention of ADHD to determine wether ADHD was diagnosed, suspected or evaluated. Subjects scoring above the usual four item cut-off for the six first items of the ASRS-v1-1 scale (positive screening for ADHD) and not previously diagnosed as ADHD were contacted by phone or mail and
clinically assessed by a senior psychiatrist specialized in ADHD working in the outpatient clinic. If uncertainty persisted after clinical evaluation, subjects were assessed using the Diagnostic Interview for Adhd in adults (DIVA) and if required, parents and family were interviewed.

Of the 539 subjects for whom medical records were reviewed 138 had a diagnosis of BD. 63 of the participants were screened positive on the ASRS v 1-1. Of these 63 subjects, 31 did not have any mention of ADHD in their files. Fourteen patients out of the 63 positively-screened subjects at the ASRS v1.1 were unfortunately unreachable. Among the remaining 49 subjects only 27 (55%)
received a diagnosis of ADHD.

Comorbid ADHD-BD subjects were younger at the onset of BD (20 years vs 26,4 years) and showed younger age at onset of the first depressive episode (19,7 years vs 27 years), higher numbers of depressive episodes (8,4 vs 5,6), more anxiety disorders (48% vs 25%), greater alcohol and substance dependence (24% vs 9% and24% vs 8%) and more boderline traits (6,2 vs 3,9).

In a specialized mood disorders clinic, 21,7% of BD subjects suffered from comorbid ADHD, suggesting that ADHD is a frequently found comorbidity in BD. This rate is nevertheless slightly higher than previously reported in other studies. More than 40 % of the subjects who scored positively at the ASRS v1-1 were not suffering from ADHD, suggesting that this scale is poorly suited to BD subjects.

The results are in agreement with those from the literature according to which the comorbidity of the two disorders is associated with a worse outcome. ADHD in BD is associated with younger age at unset of BD, more depressive episodes and more comorbid anxiety and substance use disorders.

Another finding of the study was that clinicians, most of the time, did not ascertain ADHD even if a positive score for the detection of ADHD at the ASRS v 1-1 was obtained.

In conclusion the study highlights the crucial need for clinicians to search for symptoms of ADHD in BD subjects, as the comorbidity of both disorders is frequent and associated with a poor outcome.
Clinicians should look for specific symptoms helping them to distinguish ADHD from BD. Finally, a specialist in ADHD should be consulted if any doubts about the existence of ADHD are raised.

This is a review of the article ”Comorbidity between attention deficit hyperactivity disorder (ADHD) and bipolar disorder in a specialized mood disorders outpatient clinic”, accepted 30 June 2014 in Journal of Affective Disorder 168 (2014) 161-166.

Nader Perroud, Paolo Cordera, Julien Zimmermann, Giorgio Michalopoulos, Victor Bancila, Paco Prada, Alexandre Dayer, Jean-Michael Aubry. All from the Department of Mental Health and Psychiatry, Service of psychiatric Specialities, University Hospitals of Geneva, Switzerland

Dr A Philipsens, Denmark, review for the month of November 2014