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Admixture analysis of age at onset in major depressive disorder
General Hospital Psychiatry, 08/16/2012
Zhu T et al. – The study identified three characteristically different age at onset (AAO) subgroups in individuals suffering from major depressive disorder (MDD). The subgroups may reflect different underlying neurobiological mechanisms involved.
Methods- Participants were administered the Mini-International Neuropsychiatric Interview to obtain clinical data.
- Admixture analysis was performed using the STATA module DENORMIX to identify subgroups characterized by differences in AAO.
- The best fit model was the three-component model with the following means, standard deviations and proportions: 14.60 (3.75) years (49.1%), 29.15 (6.75) years (34.1%) and 46.96 (6.06) years (16.8%) (χ2=3.64, 2 df, P=.162).
- The three subgroups were divided by AAO of 22 and 40.
- After controlling for duration of illness, there were no significant differences between the three AAO subgroups in terms of gender and psychiatric family history.
- However, the early-onset subgroup was significantly more likely to report being single compared to the intermediate- and late-onset groups.
- The proportion of individuals meeting criteria for lifetime comorbid panic disorders and obsessive–compulsive disorder did not differ significantly between the AAO groups.
- However, the early-onset group reported a higher incidence of attention-deficit/hyperactivity disorder (5.1% vs. 1.7% and 1.2%, P=.086), although this was not statistically significant.
