Comparison of the Internal State Scale to Clinician-Administered Assessments in Patients with Bipolar Disorder and Alcohol Abuse or Dependence

Abstract

Objectives: Self-report measures require less clinician time to administer than clinician-rated assessments. The Internal State Scale (ISS) is a well-validated self-report measure that assesses symptoms of mania and depression in patients with bipolar disorder (BPD). However, the ISS has never been specifically evaluated in patients with BPD and comorbid substance misuse. Substances can induce mood symptoms complicating diagnosis and mood state assessment. Methods: The ISS was compared with the Hamilton Rating Scale for Depression (HRSD), Young Mania Rating Scale (YMRS), and Brief Psychiatric Rating Scale (BPRS) in 21 patients with BPD and alcohol abuse/dependence at baseline and for up to 16 weeks postbaseline. In addition, ISS-determined mood state was compared to mood state from a structured diagnostic interview. Results: Significant baseline correlations were observed between the ISS depression subscale and HRSD, ISS activation subscale and YMRS, and ISS perceived conflict subscale and BPRS. Significant correlations of baseline to exit change scores were found between the ISS activation and YMRS, but not ISS depression and HRSD, or ISS perceived conflict and BPRS. All participants had a mixed mood state by structured diagnostic interview. The ISS diagnosed the manic/hypomanic portion of this mood state in 76% of participants but found depression in only 38%. Conclusions: As in BPD patients without substance abuse, the ISS generally showed correlations with clinician-rated scales at baseline, with less strong correlations observed on change scores. The ISS diagnosis of mania or hypomania appeared to correspond more highly than depression with the findings from a structured diagnostic interview.