Validity of the Hamilton rating scale for depression

In 26 depressed patients, a high correlation (0.89) was found between the Hamilton score and a psychiatrist's global rating and between the change (0.68) in these ratings during treatment. The Hamilton scale was able to differentiate at the 0.01 level four degrees of severity based on the global rating. Limiting the range of severity measured was found to lower significantly the correlation between the ratings. A prospective examination of a six-item sub-scale of the Hamilton scale developed by Beck and associates failed to confirm its claimed improvement in sensitivity or validity.