Diagnoses for mental health conditions among active-duty U.S. military personnel have remained steady over the last four years, with 8.3% of the total force diagnosed in 2018, compared with 8% in 2014, according to a new study from the Defense Department.
The DoD's 2018 Health of the Force study, released last month with the August edition of the Medical Surveillance Monthly Report, found that mental health appointments among active-duty troops accounted for roughly 16% of all military medical appointments, or 1.8 million outpatient visits.
The study looked at the number of diagnoses for eight mental health conditions, including adjustment disorder, alcohol dependence, anxiety, bipolar disorder, depression, post-traumatic stress disorder, psychosis and substance abuse, and found that the most common mental health diagnoses in troops were adjustment disorder, anxiety and depression.
Female service members were diagnosed with mental health conditions at rates higher than men, 12.8% compared with 7.5%, and they outpaced their male counterparts in five of eight conditions reviewed, including adjustment disorder, anxiety, depression, bipolar disorder and post-traumatic stress disorder.
Military men were diagnosed with alcohol and substance abuse disorders at rates higher than women, and both were diagnosed at the same rate -- just a tenth of 1% -- for psychosis.
The study also looked at lifetime prevalence for mental health conditions among personnel, or the diagnoses for service members across their military careers. According to the report, more than a quarter of all women, 25.2%, serving on active duty in December 2018 had a history of a mental health condition, while 16.2% of men had received a diagnosis in their lifetime.
The overall DoD rate of 8.3% in 2018 is significantly lower than the overall diagnosis rate in the United States. According to the National Association for Mental Illness, one in five adults in the U.S., or 20%, experience a mental illness in a given year, while the lifetime prevalence for mental illness is 50% among all Americans.
To conduct the study, researchers extracted the diagnostic codes assigned for mental health conditions from military medical records. They found that younger personnel below age 25 were more likely to be diagnosed than older service members, and mental health diagnoses varied across the military services in 2018, with the prevalence rate highest in the Army, at 10.7%, followed by the Navy at 7.4%, the Air Force at 7% and the Marine Corps at 6.5%.
The report authors noted their study has limitations, saying troops don't always seek care for mental health services within the military health system, which would underestimate the number of cases. Diagnoses also may have been miscoded or incorrectly transcribed, also potentially skewing the data, they added.
The report is intended to identify emerging health problems in the force and guide prevention and treatment efforts, according to the researchers.
In addition to mental health, the 2018 Health of the Force study looked at three additional conditions that affect military personnel, including injuries, obesity and sleep disorders.
The research found that 17 percent of active-duty military personnel met the clinical definition for obesity in 2018, up from 15.8% in 2014.
For the other conditions examined, the Army had the highest rates of injury and sleep disorders, while the Navy had the lowest rates of acute injuries and second-to-lowest rate for sleep disorders.
The Air Force ranked third for acute injuries and second to the Army for sleep disorders, while the Marine Corps ranked second for acute injuries and the lowest for sleep disorders.
The most common acute injuries among service members were sprains and strains, while inflammation and pain were the most common cumulative injury, accounting for nearly 87% of injury complaints.
Researchers noted that the services and the Defense Department should pay close attention to rising obesity rates, as being overweight contributes to other illnesses such as hypertension, diabetes, coronary heart disease, stroke, cancer and all-cause mortality, as well as increased health care costs.
Injuries, such as acute injuries in soldiers; back and knee joint disorders in Marines; and "repetitive microtrauma" in airmen, including microscopic tears in muscles and connective tissue caused by overuse, are a readiness concern, the authors noted.
"Given the potential for each of these conditions to contribute to decreased performance, disability and separation, further exploration of potential causes and interventions is warranted," they wrote.