Familiality of major depressive disorder and patterns of lifetime comorbidity. The NEMESIS and GenMood studies. A comparison of three samples.
BACKGROUND
Major depressive disorder (MDD) aggregates in families and is associated with high rates of lifetime axis-I comorbidity. This study examined whether familiality of MDD is associated with the presence of specific comorbid disorders, which might be an important factor to be taken into account in MDD treatment and research into MDD etiology.


METHODS
A population sample was divided into subjects with familial (f-MDD; n=432) and nonfamilial MDD (nf-MDD; n=454). Since, more comorbidity was expected in clinical cases, a clinical sample with f-MDD (n=120) was also studied. Subjects were assessed with the Composite International Diagnostic Interview and family history methods. Binary logistic regression analyses were carried out to examine the influence of familiality of MDD on comorbidity. Analyses were adjusted for potential confounders, including MDD characteristics such as severity and age of onset.


RESULTS
Dysthymia, anxiety disorders, and alcohol use disorders were significantly more prevalent in subjects with f-MDD than in subjects with nf-MDD. Clinical f-MDD was associated with more anxiety disorders and fewer alcohol use disorders than population f-MDD. After adjustment for MDD characteristics including age at onset, severity, and disease course, comorbid disorders remained more prevalent in f-MDD than in nf-MDD.


CONCLUSIONS
The instruments used in the population and the clinical samples were not identical, however, they were comparable to a substantial degree.


CONCLUSIONS
F-MDD, especially in clinical cases, appears to increase the risk of development of comorbid disorders, regardless of MDD characteristics. The link between familiality and comorbidity is important because it will aid a better understanding of the MDD phenotype, and it contributes to planning of effective treatment and to molecular genetic studies.
Department of Psychiatry (966), Radboud University Nijmegen Medical Centre, Postbox 9101, 6500 HB Nijmegen, The Netherlands.
Maaike
M
Verhagen
Annemarie
A
van der Meij
Barbara
B
Franke
Wilma A M
WA
Vollebergh
Ron
R
de Graaf
Jan K
JK
Buitelaar
Joost G E
JG
Janzing
D000328:Adult; D017668:Age of Onset; D019973:Alcohol-Related Disorders / Q000175:diagnosis / Q000453:epidemiology*; D001008:Anxiety Disorders / Q000175:diagnosis / Q000453:epidemiology*; D015897:Comorbidity; D003865:Major Depressive Disorder / Q000145:classification / Q000175:diagnosis / Q000453:epidemiology*; D019263:Dysthymic Disorder / Q000175:diagnosis / Q000453:epidemiology*; D005260:Female; D006801:Humans; D015994:Incidence; D016015:Logistic Models; D008297:Male; D008875:Middle Aged; D009426:Netherlands / Q000453:epidemiology; D015995:Prevalence; D012307:Risk Factors; D012720:Severity of Illness Index; D013997:Time Factors