Sex Differences in a Network Model of Depressive Symptoms

Major Depressive Disorder (MDD) is one of the most prevalent mental health disorders, with a lifetime prevalence rate of 13-16% and 12-month prevalence rates of 5-7%. It has long been established that the rates of MDD in females is two to three times that of males. Previous research has examined sex differences in the occurrence and severity of MDD symptoms, primarily indicating greater severity of appetite increase and weight gain in females compared to males. The majority of previous research has been conducted assuming the latent factor model that MDD accounts for the symptoms of depression, and sex operates as a mediator or moderator between the latent variable and MDD, or between MDD and its symptoms. The present study used network analysis to examine whether there are sex differences in the relations between symptoms of depression, which might be an important factor for understanding sex differences in prevalence rates of MDD. The present study compared networks of DSM MDD symptoms between currently depressed females and males, and separate networks that also included other symptoms commonly associated with depression (e.g., anxiety, anger). Sex differences were examined using jointly estimated networks, and a Network Comparison Test (NCT) for the independently estimated networks. Results indicated no sex differences in depression symptom networks. These results indicate that depressive symptom networks, or the relations between symptoms are not an important factor for understanding the disparity in sex differences in MDD prevalence rates. Interestingly, non-DSM symptoms were among the strongest and most important symptoms within the network, suggesting future research and diagnostic criteria should consider inclusion of non-DSM symptoms associated with MDD