The specific phenotype of depression in recent onset schizophrenia spectrum disorders: A symptom profile and network comparison to recent onset major depressive disorder without psychotic features

The specific phenotype of depression in recent-onset schizophrenia spectrum disorders (SSD) and its relation to non-psychotic depression is unknown. Symptom profile and network analysis are complementary statistical techniques that may provide important insights into the presentation and relative importance of individual symptoms that give rise to depression. The aim of the current study was to characterise the profile and network of depressive symptoms in SSD and compare it to individuals with major depressive disorder (MDD) without psychotic features. This study involved analysis of baseline data pertaining to 109 individuals with comorbid SSD and depression and 283 with MDD without psychotic features. Study cohorts were the Psychosis Recent Onset GRoningen Survey (PROGR-S) and Youth Depression Alleviation (YoDA) trials, respectively. Profile and network analyses revealed that SSD and MDD differed in the profile and relative importance of individual depressive symptoms. While reported sadness was the primary hallmark of depression in both SSD and MDD, individuals with depression in SSD were more likely to sleep more, and have lower lassitude and pessimism. While sadness had great importance in MDD and SSD, in SSD but not MDD lassitude, sleep, appetite, concentration difficulties, and inability to feel were important in the network of depressive symptoms. The specific phenotype of depression might be different in SSD compared to MDD. Symptom inequivalence or underlying functional mechanisms in SSD might result in depression in SSD that is similar to MDD with atypical features.