Reliability and validity of the Massachusetts general hospital cognitive and physical functioning questionnaire.

BACKGROUND

We have recently developed the Massachusetts General Hospital Cognitive and Physical Functioning Questionnaire (CPFQ), a brief scale to measure cognitive and executive dysfunction in mood and anxiety disorders, and we here report on its reliability and validity.

METHODS

The internal consistency of the CPFQ was assessed by computing Cronbach's coefficient alpha based upon the average intercorrelation of the 7 items of the CPFQ in a sample of depressed outpatients and by factor analyzing data from the same sample to confirm that the scale is unifactorial and measuring a single construct. Test-retest reliability of the CPFQ was assessed in a different sample of depressed outpatients by computing Pearson's correlation coefficient between pretreatment screening scores and pretreatment baseline scores. Sensitivity to change of the CPFQ was assessed by computing the dependent t test for the subjects in the active treatment condition in the second sample of depressed outpatients. Finally, convergent validity for the CPFQ was assessed in two different ways.

RESULTS

We found that the CPFQ is a unifactorial scale, with strong internal consistency. It has good temporal stability as indicated by high test-retest reliability. The CPFQ was also found to be sensitive to change with treatment and displayed convergent validity by significant correlations with other measures of sleepiness, fatigue, apathy and neuropsychological functioning. Although, as expected, the CPFQ was significantly correlated with a measure of depression, the moderate correlation (r approximately 0.30) indicates that the CPFQ is measuring a different construct.

CONCLUSION

In summary, the CPFQ is a unifactorial scale, with strong internal consistency, good temporal stability and sensitivity to change with treatment. Further studies will be needed to assess the validity and reliability of this instrument in other psychiatric and neuropsychiatric conditions associated with cognitive dysfunction.