Screening for Depression – Why Girls May Benefit
By: Katherine M. Reding, Ph.D.
Major Depressive Disorder (MDD) is one of the most common mental health disorders in the United States. According to the National Institute of Mental Health, in the year 2014 alone, approximately 7% of the population, or 5.7 million adults, aged 18 or over experienced at least one major depressive episode. Of these adults, women were almost twice as likely to have experienced an MDD episode, such that 8.2% of women compared to 4.8% of men reported an episode in 2014. In general, women are two to three times more likely than men to develop stress-related psychopathology, such as MDD, across their lifetime. Importantly, MDD is also common in adolescents between ages 12 and 18. Approximately 8% of adolescents have been diagnosed with MDD, according to a recent study from the U.S. Preventive Services Task Force (USPSTF), an independent and volunteer panel of experts in disease prevention and evidence-based medicine.
Throughout young adulthood, between the ages of 19 and 31, being female is one of the largest risk factors for developing MDD. Although the USPSTF report identified the ‘female sex’ as a risk factor for developing MDD in adolescents, it lacked any discussion regarding the sex and gender differences in disease onset, screening, and treatment. In fact, sex-differences in MDD onset emerge around the time of puberty, and girls show a spike in onset at age 14, such that the two-fold increase in female prevalence of MDD seen in adulthood is apparent beginning at 15 years of age.
Exactly why sex differences in MDD emerge during adolescence is still in debate. Some researchers suggest that it is the biological process of puberty, or the maturation of the female reproductive system and the production of ovarian hormones such as estrogen and progesterone, that causes the increased susceptibility to depression in adolescent girls. Unfortunately, the correlation between female hormones and teenage mental health is not a simple one to demonstrate. The process of puberty is not isolated to reproductive biology, but is also a time of increased physical, social, and emotional changes.
Another potent predictor for the development of depression in women is a history of exposure to stressful life events. The prevalence of MDD in women may be due to a combination of exposure to stressful or traumatic events coinciding with the production of ovarian hormones leading up to menarche when girls begin menstruating. Dr. Amy Marshall, a clinical psychologist from Pennsylvania State University, suggests that traumatic events such as major disasters, witnessing family violence, physical assault, or sexual assault occurring between 6 years prior to menarche and 2 years afterwards were a significant risk factor for developing depression in young women. Peak risk resulted when traumatic events occurred 2 to 6 years prior to menarche, when ovarian hormones are in the early stages of production.
As an update to their 2009 recommendations, the USPSTF found that there is essentially “no harm” in screening for and treating MDD in adolescents age 12 to 18. Previously, the USPSTF had limited its recommendations for screening to only those adolescents with access to psychotherapy due to concerns regarding the negative side-effects and harms of pharmacotherapy in adolescents. Current recommendations suggest universal screening due to more recent findings that show no significant harm resulting from using pharmacotherapy, psychotherapy, collaborative care, psychosocial support interventions, or complementary and alternative medicine approaches. Instead, the most harm appears to come from not detecting and not treating adolescent onset MDD, as one episode of MDD in adolescence greatly increases the risk of recurrent episodes throughout adulthood.
Despite broadening their screening recommendation, the report unenthusiastically stated that “there is moderate certainty that the net benefit [of screening for MDD] is moderate to substantial,” which does not appear to be a huge vote of confidence on their own findings. This seemingly indifferent review is a direct result of the limited data available on the outcomes of adolescent screenings for MDD. In fact, the USPSTF found no studies directly assessing the benefits or harms of screening for MDD in adolescents, making it impossible to detect actual benefits derived from the screening process. It is also important to note, that the USPSTF could make no recommendations for screening or treating children younger than 11 years of age, as no studies that were found that included children of those ages.
In conclusion, healthcare providers and researchers must begin to collect data on MDD screening and treatment outcomes in teens to determine just how beneficial these screening recommendations might be. The benefits to women’s health, as well as men’s health, across the lifespan may be significant, but only time and data will tell.