Postpartum depression in the NICU: an examination of the factor structure of the Postpartum Depression Screening Scale.

PURPOSE

The purpose of this research was to examine the construct validity of scores from the Postpartum Depression Screening Scale administered to mothers of infants in a neonatal intensive care unit.

SUBJECTS

Two samples (n = 385 and n = 110) of mothers with infants in a neonatal intensive care unit in the south-central region of the United States completed the Postpartum Depression Screening Scale 2 weeks postpartum. Both samples were similar in race and education level but differed according to marital status.

DESIGN

Study 1 was retrospective and descriptive, whereas study 2 was prospective and descriptive.

METHODS

In study 1, confirmatory factor analysis was used to evaluate the originally proposed 7-factor structure and a 1-factor model. Because of overly high correlations between 3 of the factors, a revised 5-factor model was also tested. In study 2, confirmatory factor analysis was again used to test the construct validity or goodness of fit of the 7-factor and 5-factor models.

MAIN OUTCOME MEASURES

Goodness-of-fit indices and factor pattern coefficients.

PRINCIPAL RESULTS

In study 1, high correlations between 3 of the factors in the 7-factor model did not converge. Thus, a 5-factor model was also tested. This model had reasonable fit: χ= 1339.70 (550); P < 0.01; comparative fit index = 0.85; root mean square error of approximation = 0.06; and 90% confidence interval for root mean square error of approximation = 0.058 to 0.067. In study 2, confirmatory factor analysis was again used to test the construct validity or goodness of fit of the 7-factor and 5-factor models. Results for the 7-factor model indicated unacceptable fit: χ (539) = 959.10; P < 0.01; comparative fit index = 0.76; and root mean square error of approximation = 0.09. The 5-factor model was also poor: χ (550) = 992.95; P < 0.01; comparative fit index = 0.75; and root mean square error of approximation = 0.09.

CONCLUSIONS

Although the construct validity of the 7-factor model of the PDSS was not supported for this sample of mothers, additional factor analytic work was used to develop and provide initial validation of a 5-factor model. Future research should continue to explore the unique experiences of mothers in the NICU who experience postpartum depression.