The Clinician-Administered Rating Scale for Mania (CARS-M): development, reliability, and validity

Area of Science:

• Psychiatry
• Clinical Psychology
• Psychometric Evaluation

Background:

• Existing scales for assessing manic symptomatology have limitations impacting clinical and research utility.
• There is a need for a more precise and reliable instrument to evaluate mania.
• The Clinician-Administered Rating Scale for Mania (CARS-M) was developed to address these deficiencies.

Purpose of the Study:

• To develop and validate the Clinician-Administered Rating Scale for Mania (CARS-M).
• To assess the reliability and validity of the CARS-M in a patient population.
• To compare the CARS-M with existing mania rating scales.

Main Methods:

• The CARS-M was developed and normed on 96 patients with mixed diagnoses.
• Interrater reliability was assessed using 14 videotaped interviews and multiple raters.
• Test-retest reliability was evaluated on 36 patients.
• Principal components analysis was used to determine the factor structure.
• Internal validity was assessed by correlating items with total factor scores.
• Correlation with the Mania Rating Scale (MRS) was calculated.

Main Results:

• High interrater reliability (ICC=0.81 for items, 0.93 for total scores) was established.
• Test-retest reliability was significant for both identified factors (mania and psychosis), ranging from 0.78 to 0.95.
• All items showed significant correlations with their respective total factor scores, indicating strong internal validity.
• A high correlation (0.94) was found between CARS-M total scores and MRS total scores.
• Principal components analysis identified two factors: mania and psychosis.

Conclusions:

• The CARS-M is a reliable and valid instrument for measuring manic symptomatology.
• The scale demonstrates methodological improvements leading to enhanced precision and clinical utility.
• CARS-M offers a valuable tool for both clinical assessment and research in mania.