The association between latent depression subtypes and remission after treatment with citalopram: A latent class analysis with distal outcome.

BACKGROUND: The objectives were to characterize latent depression subtypes by symptoms, evaluate sex differences in and examine correlates of these subtypes, and examine the association between subtype and symptom remission after citalopram treatment.

METHODS: Latent class analysis was applied to baseline data from 2772 participants in the Sequenced Treatment Alternatives to Relieve Depression trial. Indicators were from the Quick Inventory of Depressive Symptomatology. Separate multinomial logistic models identified correlates of subtypes and the association between subtype and the distal outcome of remission.

RESULTS: Four latent subtypes were identified: Mild (men: 37%, women: 27%), Moderate (men: 24%, women: 21%), Severe with Increased Appetite (men: 13%, women: 22%), and Severe with Insomnia (men: 26%, women: 31%). Generalized anxiety disorder, bulimia, and social phobia were correlated with Severe with Increased Appetite and generalized anxiety disorder, post-traumatic stress disorder, and social phobia with Severe with Insomnia. Relative to those with the Mild subtype, those with Severe with Increased Appetite (odds ratiomen (OR): 0.48; 95% confidence interval (CI): 0.25-0.92; OR women: 0.59; 95% CI: 0.41-0.86) and those with Severe Depression with Insomnia (ORmen: 0.65; 95% CI: 0.41-1.02; ORwomen: 0.45; 95% CI: 0.32-0.64) were less likely to achieve remission.

LIMITATIONS: The sample size limited exploration of higher order interactions.

CONCLUSIONS: Insomnia and increased appetite distinguished latent subtypes. Sex and psychiatric comorbidities differed between the subtypes. Remission was less likely for those with the severe depression subtypes. Sleep disturbances, appetite changes, and other mental disorders may play a role in the etiology and treatment of depression.