Bipolar disorder comorbid in high-functioning autism
MedWire News: Patients with high-functioning autism spectrum disorder (ASD) are more likely to have comorbid bipolar disorder than comorbid major depressive disorder, conclude Japanese researchers.
While previous studies have indicated that the main psychiatric comorbidity in individuals with ASD is depression, the majority of investigations have focused on individuals with low intellectual abilities, rather than those with a normal intelligence quotient.
T Munesue and colleagues from Kanazawa University Hospital therefore studied 44 outpatients with high-functioning ASD aged 12 years or over who had an IQ of at least 70 on the Wechsler Intelligence Scale.
In all, nine patients had autistic disorder, 27 had Asperger disorder, and eight had pervasive developmental disorder otherwise specified. A mood disorder was demonstrated in 16 (36.4%) patients.
There were no significant differences between patients with and without mood disorder in terms of gender, index age, age at intake, follow-up period, rate of mood disorder in first- and second-degree relatives, and IQ.
Of the 16 patients with a mood disorder, four had major depressive disorder, two had bipolar I disorder, six had bipolar II disorder, and four had bipolar disorder not otherwise specified, indicating that bipolar disorder accounted for 75% of cases.
Asperer disorder was diagnosed in 12 patients with comorbid mood disorder, while four had pervasive developmental disorder not otherwise specified, the team reports in the Journal of Affective Disorders.
Noting the association between ASD and bipolar disorder, they write: “There are some biologic similarities between the two disorders: for example, decreased serum melatonin levels, and disturbances of sleep and circadian rhythms. Pleiotropic effects of the same genes could lead to a combination of these two disorders.”