epidemiology of personality disorders in the U.S. Navy, The

Military Medicine, Jul 2003 by Gunderson, E K Eric, Hourani, Laurel L

This study evaluated the incidence of first hospitalizations for personality disorders and their association with career outcomes for Navy enlisted personnel. Gender differences, rates for subtypes, and changes in hospital admission rates over time also were examined. Personnel who were first hospitalized with a personality disorder between 1980 and 1988 were followed through 1992 and were compared with a control group that did not manifest such pathology. Hospitalized personality disorder cases demonstrated pathology very early in their military careers, which was judged to have been present prior to enlistment in more than one-half of the cases. Women were more likely than men to have a first hospitalization for personality disorders. Rates in both men and women increased during the latter one-half of the 1980s and decreased during the early 1990s.

Introduction

Personality disorders (PDs) are a leading cause of premature discharges of personnel from the naval service.1 Clinical studies have shown that individuals with PDs have significant difficulty adjusting to military life, have limited coping skills, and may be unable to respond to the leadership, counseling, and therapeutic measures available in a military setting.2 Although research interest in PDs was spurred with the assignment of PDs to their own axis (axis II) in the Diagnostic Statistical Manual (DSM-III)3 in 1980, little epidemiologic research on PDs has been conducted in the military since then, and neither the prevalence nor incidence of these disorders in known.4 The military population provides a unique opportunity for longitudinal study of these relatively common but poorly understood conditions. PD cases generally are not hospitalized in the civilian community. In the Navy, because of confined living and working conditions and requirements for personal reliability, cooperation, and team effort, traits that are characteristic of PD cases are conspicuous and disruptive and more often lead to hospitalization for evaluation.

A number of longitudinal studies of PD were conducted in the Navy population during the 1970s.5-8 These studies documented the major burden imposed on Navy commanders and medical facilities by PD cases and defined prognostic indicators for personnel hospitalized with these diagnoses. Early detection and accurate assessment of the severity of character pathology have remained a challenge to the appropriate management of these individuals. Furthermore, large numbers of women entering the Navy during the 1980s and new duty assignment policies permitting women to serve aboard ship have made it possible to examine gender differences and prognosis in diagnostic subtypes and to compare PD hospitalization rates and career outcomes among women and men. The purpose of the present study was to examine updated hospitalization data for PD among active duty Navy men and women and to extend knowledge of these diagnoses, which remain poorly understood. The present study evaluated the nature and impact of such disorders and compared PD cases with a control group that did not manifest such pathology.

Methods

The population studied included all enlisted personnel on active duty in the Navy who were first hospitalized for PDs during 1980 to 1988. This period was chosen because diagnostic categories were relatively well defined and stable9 and large numbers of women were enlisted in the Navy, making meaningful comparative studies by gender possible. Also, it was necessary to allow a period of at least 4 years of follow-up for short-term outcome studies. To extend the analysis of annual rates, and because shipboard medical facilities discontinued reporting of hospitalizations in the 1990s, a supplemental analysis of rates for shore-based personnel was conducted for the time period 1980 to 1995.

PDs are described in the Glossary of Mental Disorders in International Classification of Diseases9 (ICD-9-CM) as follows: "Deeply ingrained maladaptive patterns of behavior generally recognizable by the time of adolescence or earlier and continuing most of adult life." ICD-9, the diagnostic nomenclature used by the Department of Defense, began incorporating the classification system of the Diagnostic and Statistical Manual of Mental Disorders, Edition 3 (DSM-III), by the American Psychiatric Association by 1980.3 A number of new diagnostic subcategories were added in 1986, but only major subtypes are used in the present study. Major current categories and ICD-9 codes are shown in Table I with numbers of cases during 1980 to 1988.

Diagnoses were made by attending physicians, often psychiatrists, at major urban military medical centers at the time of discharge from the hospital after a period of observation and, in many cases, psychological testing. Diagnoses were important in clinical and administrative decisions concerning disposition of patients. A total PD group consisting of all major subgroups shown in Table I (excluding 23 men and 1 woman who were missing demographic data) (N = 20,709) was formed to compare with a control group of randomly selected personnel (N = 11,634) who served at some time during 1980 to 1988 but were never hospitalized for mental disorder. Randomness for the control group was ensured by selecting individuals with social security numbers that ended in 5.