Conclusions : International differences in prescriber behaviour may influence , and in turn be influenced by , the conduct of clinical trials .
Objective : International differences are thought to exist in dosages used by clinicians treating mood disorders .
This study examined international dosage differences in antidepressant clinical trials , using a data base formed and maintained as a component of a Cochrane review of comparative clinical trials of fluoxetine .
Efficacy and response time to sertraline versus fluoxetine in the treatment of unipolar major depressive disorder.
BACKGROUND Few studies have compared the treatment efficacy of the 2 selective serotonin reuptake inhibitors sertraline and fluoxetine . METHOD A r and omized , single-blind , parallel-group study of 10 weeks ' duration comparing the efficacy of sertraline , 50 mg/day ; sertraline , 100 mg/day ; and fluoxetine , 20 mg/day , was conducted in 44 psychiatric out patients with DSM-IV unipolar major depressive disorder . Antidepressant dosages were doubled at 6 weeks for subjects who had not achieved remission . Primary outcome measurements included the 21-item Hamilton Rating Scale for Depression ( HAM-D ) and the Clinical Global Impressions-Improvement scale ( CGI-I ) , with scores of < or = 7 on the HAM-D and < or = 2 on the CGI-I representing a positive treatment response , i.e. , remission . RESULTS At 4 weeks , significant differences in rate of positive treatment response were noted , with 0 % for sertraline , 50 mg ; 46 % for sertraline , 100 mg ; and 31 % for fluoxetine , 20 mg ( p = .023 ) . At 6 weeks , positive treatment response rates were 21 % , 43 % , and 31 % for subjects taking 50 mg of sertraline , those taking 100 mg of sertraline , and those taking 20 mg of fluoxetine , respectively , with treatment groups no longer differing significantly from each other . In subjects for whom antidepressant dose was doubled at week 6 , response rates at week 10 ( 4 weeks on increased dose ) were 40 % for sertraline , 100 mg ; 43 % for sertraline , 200 mg ; and 55 % for fluoxetine , 40 mg . CONCLUSION Subjects taking sertraline , 100 mg , and  fluoxetine , 20 mg , demonstrated an earlier treatment response compared with subjects taking sertraline , 50 mg . For patients without a positive response at 6 weeks , an increased antidepressant dose result ed in remission for a substantial proportion of patients when assessed 4 weeks later
Conclusions : International differences in prescriber behaviour may influence , and in turn be influenced by , the conduct of clinical trials .
Objective : International differences are thought to exist in dosages used by clinicians treating mood disorders .
This study examined international dosage differences in antidepressant clinical trials , using a data base formed and maintained as a component of a Cochrane review of comparative clinical trials of fluoxetine .