The Spectra: Indices of Psychopathology: Construct Validity and Sensitivity to Change in an Inpatient Psychiatric Sample

The current study evaluated the construct validity and sensitivity to change of the Spectra: Indices of Psychopathology in an inpatient psychiatric sample (N = 83). Admission diagnoses were generally split between Depression / Anxiety (27.7%), Substance Use Disorders (27.7%), Bipolar Disorder (22.9%), and Primary Psychotic Disorders (21.7%). Results indicate the three higher-order spectra scores (Internalizing, Externalizing, and Reality Impairing) effectively differentiated between known clinical groups, with effect sizes (η_p²) ranging from 0.13 (Internalizing) to 0.44 (Externalizing). Hypothesized spectra scores also discriminated between groups with and without a history of suicide attempts (Internalizing Cohen’s d = 0.60), arrests within the last five years (Externalizing Cohen’s d = 0.60), and a primary psychotic disorder diagnosis at admission (Reality Impairing Cohen’s d = 1.12). Concurrent validity was supported when examining patterns of correlations with the Personality Assessment Inventory; all target correlations were statistically significant (p < 0.05) and ranged from r = 0.36 (Psychotic Experience) to r = 0.76 (Depression). Finally, sensitivity to change assumptions were met when comparing admission and discharge scores for the subsample (N = 47) of patients who also completed the instrument at discharge. The implications with respect to application and clinical utility in acute (inpatient) settings are discussed.