Northwestern University Department of Psychology, Evanston, IL, 60208, USA.
Weill Cornell Medical College, New York, NY, 10065, USA.
Transl Psychiatry. 2019 Sep 16;9(1):229. doi: 10.1038/s41398-019-0563-x.
Depressive symptoms are highly prevalent in psychotic populations and result in significant functional impairment. Limited knowledge of whether depressive symptoms are invariant across stages of illness curtails our ability to understand how these relate to illness progression. Clarifying the latent structure of depressive symptoms across stages of illness progression would aid etiological conceptualizations and preventive models. In the present study, one-factor (including all items) and two-factor (depression/hopelessness and guilt/self-depreciation) solutions were specified through confirmatory factor analysis (CFA). Measurement invariance analyses were undertaken across schizophrenia (SCZ; n = 312) and clinical high-risk (CHR; n = 175) groups to estimate whether the same construct is being measured across groups. Clinical correlates of the factors were examined. Results indicated that CHR individuals had a greater proportion of mood disorder diagnoses. Metric invariance held for the one-factor solution, and scalar invariance held for the two-factor solution. Notably, negative symptoms did not correlate with depressive symptoms in the SCZ group, though strong correlations were observed in CHR individuals. Positive symptoms were comparably associated with depressive symptoms in both groups. Results suggest depressive symptoms are more prevalent in CHR individuals. Targeting these symptoms may aid future efforts to identify risk of conversion. Further, some depressive symptoms may be systematically more endorsed in CHR individuals. Separating into depression/hopelessness and guilt/self-depreciation scores may aid comparability across stages of illness progression, though this issue deserves careful attention and future study.
抑郁症状在精神病患者中非常普遍，导致严重的功能障碍。由于我们对抑郁症状是否在疾病各个阶段保持不变的了解有限，因此限制了我们理解这些症状与疾病进展之间关系的能力。阐明疾病进展各个阶段的抑郁症状的潜在结构将有助于病因学概念化和预防模型。在本研究中，通过验证性因素分析（CFA）指定了单因素（包括所有项目）和双因素（抑郁/绝望和内疚/自我贬低）解决方案。进行了跨精神分裂症（SCZ；n=312）和临床高风险（CHR；n=175）组的测量不变性分析，以估计是否在组间测量相同的结构。检查了这些因素的临床相关性。结果表明，CHR 个体的情绪障碍诊断比例更高。单因素解决方案的度量不变性成立，双因素解决方案的标度不变性成立。值得注意的是，SCZ 组的阴性症状与抑郁症状不相关，而 CHR 个体中则存在强烈的相关性。阳性症状在两组中均与抑郁症状相当相关。结果表明，CHR 个体中抑郁症状更为普遍。针对这些症状可能有助于未来识别转化风险的努力。此外，CHR 个体可能会系统地更认可某些抑郁症状。将分数分为抑郁/绝望和内疚/自我贬低分数可能有助于比较疾病进展的各个阶段，但这个问题值得谨慎关注和进一步研究。
