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 o-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.