A comparative meta-analysis of Clinical Global Impressions change in antidepressant trials.

Two scales of the Clinical Global Impressions (CGI) Scale are frequently used in antidepressant trials. No research has systematically addressed how CGI change compares to change on established measures such as the Hamilton Depression Rating Scale (HAM-D), Montgomery-Asberg Depression Rating Scale, or Beck Depression Inventory. The current meta-analysis examined 75 antidepressant trials in which the CGI was used along with at least one other popular depression measure. The CGI-Severity scale was significantly more conservative than the HAM-D in rating change in double-blind trials, but not in open trials. The Beck Depression Inventory was significantly more conservative than the CGI-Severity. The CGI-Improvement scale was significantly more liberal than the HAM-D or Montgomery-Asberg Depression Rating Scale. Rater bias or scale content may explain differences between measures. Given the often substantial differences between instruments, researchers should use a variety of measures rather than relying on any single tool in assessing treatment response.