Assessment of Trait and State Aspects of Depression in Schizophrenia

Depression and negative symptoms can be difficult to distinguish in schizophrenia. Assessments for negative symptoms usually account for the longitudinal nature of these symptoms, whereas instruments available to measure depression mainly assess current or recent symptoms. This construct difference may confound comparison of depres-sive and negative symptoms in schizophrenia because both domains may have trait-like aspects. We developed an instrument to measure both longitudinal “trait ” as well as recent “state ” symptoms of depression and tested this instrument (Maryland Trait and State Depression [MTSD] scale) in a sample of 98 individuals with schizophrenia or schizoaffective disorder and 115 community participants without psychotic illness. Exploratory factor analysis of the MTSD revealed 2 factors accounting for 73.4 % of th