The longitudinal study of personality disorders: history, design considerations, and initial findings.

The Longitudinal Study of Personality Disorders (LSPD) began in 1990 and it is the first NIMH-funded prospective multiwave longitudinal study of all DSM-defined personality disorders (PDs). The LSPD, now in its 16th year, has focused on several major issues including: (a) the epidemiology of the PDs; (b) the stability of individual differences and mean levels of PD features over time; (c); patterns of individual growth in PD features over time; (d) the development of a neurobehavioral model that links personality and personality disorder; (e) specification of those neurobehavioral systems predicting change in borderline personality disorder; and (f) illumination of simultaneous growth processes in neurobehavioral systems and PD. The LSPD possesses a number of methodological enhancements designed to increase the validity of the longitudinal findings such as a prospective multiwave design, use of a validated structured interview and well-known self-report instrument for Axis II assessments, double measurement of all major constructs under study, use of blinded interviewers for all interview Axis II assessments, and use of a community sample. The history and context in which the LSPD was developed is reviewed, methodological issues related to the study of PDs are discussed, primary LSPD findings to date are summarized, and future directions of the LSPD are introduced.