According to the results of a meta-analysis published in Psychological Medicine, a significant portion of individuals with first-episode schizophrenia (FES) will also experience a full-threshold depressive disorder.
Sarah E. Herniman, of the University of Melbourne in Australia, led a systematic review and meta-analysis of all literature regarding FES and depression. Five databases were screened for peer-reviewed English language studies describing depression in FES: PsychINFO, Embase, MEDLINE, Web of Science, and Evidence-Based Medicine reviews. Studies of individuals with affective psychotic disorders were excluded.
Outcomes of interest were the pooled severity of depressive symptoms, as well as the pooled prevalence of depressive disorder or depressive caseness, which refers to severity cut-off scores on validated depression measures. The demographic, illness, functional, and treatment correlates of depressive psychopathology were also investigated. Methodologic quality was assessed using a 5-item scale adapted from the Newcastle Ottawa Quality Assessment Form for Cohort Studies, and random-effects models were conducted for each primary outcome.
Ultimately, 40 studies comprising 4041 participants (mean age range, 15.4-38.3 years) were included in the analyses. Across studies, the mean proportion of women in study cohorts ranged from 13.6% to 56.1%. Study quality varied, with a mean Newcastle-Ottawa score of 4.6 of a possible 10.
In 7 samples (n=855), the pooled prevalence of depressive disorder was 26.0% (95% CI, 22.1-30.3) with moderate heterogeneity and no proof of publication bias. Eleven studies (n=1312) assessing caseness yielded a pooled prevalence of 43.9% (95% CI, 30.3-58.4) with high heterogeneity and no proof of publication bias. Among 38 samples (n=3180) that reported symptom severity, the percentage of patients with maximum depression severity was 25.1 (95% CI, 21.49-28.68), although evidence of publication bias and heterogeneity were high.
Additionally, according to meta-regression, greater severity of depressive symptoms was significantly associated with increased severity of positive (P =.002) and negative (P =.003) schizophrenia symptoms. Prevalence of depressive caseness (P =.018) and depression severity (P <.001) was higher in the acute phase of FES compared with the postacute phase. Caseness was associated with younger individuals (P <.003) and with men (P <.001).
As study limitations, investigators noted that the use of different depression instruments across studies may have affected the precision prevalence calculations. Additionally, substantial overlap exists between depressive symptoms and negative symptoms, which may have had an impact on meta-regression results.
“Depressive psychopathology is prominent in FES, manifesting not only as superimposed comorbidity but also as an inextricable symptom domain,” the study authors wrote. They also stated, “Assessment of depressive psychopathology is therefore critical at first presentation to treatment services to improve outcomes and prevent suicide in FES”.