Modeling trajectory of depressive symptoms among psychiatric inpatients: a latent growth curve approach

Changes in the parameters of inpatient psychiatric care have inspired a sizable literature exploring correlates of prolonged intervention as well as symptom change over varying lengths of hospitalization. However, existing data offer limited insight regarding the nature of symptom change over time. Objectives of this longitudinal research were to (1) model the trajectory of depressive symptoms within an inpatient psychiatric sample, (2) identify characteristics associated with unique patterns of change, and (3) evaluate the magnitude of expected gains using objective clinical benchmarks.

Participants included 1,084 psychiatric inpatients treated between April 2008 and December 2010. Latent growth curve modeling was used to determine the trajectory of Beck Depression Inventory II depressive symptoms in response to treatment. Age, gender, trauma history, prior hospitalization, and DSM-IV diagnoses were examined as potential moderators of recovery.

Results indicate a nonlinear model of recovery, with symptom reductions greatest following admission and slowing gradually over time. Female gender, probable trauma exposure, prior psychiatric hospitalization, and primary depressive diagnosis were associated with more severe trajectories. Diagnosis of alcohol/substance use, by contrast, was associated with more moderate trajectories. Objective benchmarks occurred relatively consistently across patient groups, with clinically significant change occurring between 2-4 weeks after admission.

The nonlinear trajectory of recovery observed in these data provides insight regarding the dynamics of inpatient recovery. Across all patient groups, symptom reduction was most dramatic in the initial week of hospitalization. However, notable improvement continued for several weeks after admission. Results suggest that timelines for adequate inpatient care are largely contingent on program-specific goals.