{"id":50826,"date":"2014-10-17T10:28:40","date_gmt":"2014-10-17T14:28:40","guid":{"rendered":"http:\/\/1boringoldman.com\/?p=50826"},"modified":"2014-10-18T05:48:19","modified_gmt":"2014-10-18T09:48:19","slug":"more-wagner-et-al","status":"publish","type":"post","link":"https:\/\/1boringoldman.com\/index.php\/2014\/10\/17\/more-wagner-et-al\/","title":{"rendered":"more Wagner et al<\/em>…"},"content":{"rendered":"
I know I sometimes get kind of hung up on numbers, and it just happened. I was looking at Wagner et al in the last post because it was ghost-written, but I did read the abstract and something stuck with me. It’s highlighted in red below, "[effect size=2.9]<\/font><\/strong>". The effect size is a measure of the strength of an effect and is the simplest of calculations: it’s the difference in the means of the two groups divided by the standard deviation. Besides being an index of the strength of an effect, it also normalizes things so different studies can be compared. The usual range is 0.25 = weak<\/font><\/strong>, 0.50 = moderate<\/font><\/strong>, and 0.75 = strong<\/font><\/strong>. So what’s with effect size=2.9<\/font><\/strong>? It doesn’t make any sense. So I went back and pulled the whole paper to calculate it myself. Curious George, I guess…<\/div>\n
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A randomized, placebo-controlled trial of citalopram for the treatment of major depression in children and adolescents.<\/a><\/div>\n
by Wagner KD, Robb AS, Findling RL, Jin J, Gutierrez MM, Heydorn WE.<\/div>\n
American Journal of Psychiatry<\/font><\/strong>. 2004 161[6]:1079-1083.<\/div>\n

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OBJECTIVE:<\/font><\/strong><\/u> Open-label trials with the selective serotonin reuptake inhibitor citalopram suggest that this agent is effective and safe for the treatment of depressive symptoms in children and adolescents. The current study investigated the efficacy and safety of citalopram compared with placebo in the treatment of pediatric patients with major depression.<\/div>\n
METHOD:<\/font><\/strong><\/u> An 8-week, randomized, double-blind, placebo-controlled study compared the safety and efficacy of citalopram with placebo in the treatment of children [ages 7-11] and adolescents [ages 12-17] with major depressive disorder. Diagnosis was established with the Schedule for Affective Disorders and Schizophrenia for School-Age Children-Present and Lifetime Version. Patients [N=174] were treated initially with placebo or 20 mg\/day of citalopram, with an option to increase the dose to 40 mg\/day at week 4 if clinically indicated. The primary outcome measure was score on the Children’s Depression Rating Scale-Revised; the response criterion was defined as a score of <<\/u> 28.<\/div>\n
RESULTS:<\/font><\/strong><\/u> The overall mean citalopram dose was approximately 24 mg\/day. Mean Children’s Depression Rating Scale-Revised scores decreased significantly more from baseline in the citalopram treatment group than in the placebo treatment group, beginning at week 1 and continuing at every observation point to the end of the study [effect size=2.9]<\/font><\/strong>. The difference in response rate at week 8 between placebo [24%] and citalopram [36%] also was statistically significant. Citalopram treatment was well tolerated. Rates of discontinuation due to adverse events were comparable in the placebo and citalopram groups [5.9% versus 5.6%, respectively]. Rhinitis, nausea, and abdominal pain were the only adverse events to occur with a frequency exceeding 10% in either treatment group.<\/div>\n
CONCLUSIONS:<\/font><\/strong><\/u> In this population of children and adolescents, treatment with citalopram reduced depressive symptoms to a significantly greater extent than placebo treatment and was well tolerated.<\/div>\n

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Well, they give us the mean CDRS-R scores at the baseline and the standard deviations…<\/div>\n
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… Mean Children’s Depression Rating Scale Revised scores at baseline were 58.8 [SD=10.9] and 57.8 [SD=11.1] in the citalopram and placebo groups, respectively, indicative of moderately severe illness.<\/div>\n<\/blockquote>\n
And they show us that there’s about a 5 point difference at week 8 on the graph, but they didn’t give us either the Means or the Standard Deviations at week 8 anywhere that I could find. Since the Formula is Effect Size<\/font><\/strong> =<\/font><\/strong> [Difference in the Means<\/font><\/strong>] ÷<\/font><\/strong> [Standard Deviation<\/font><\/strong>], we could work backwards as in 2.9<\/font><\/strong> =<\/font><\/strong> 5<\/font><\/strong> ÷<\/font><\/strong> [Standard Deviation<\/font><\/strong>] which comes out with a Standard Deviation<\/font><\/strong> =<\/font><\/strong> 1.72<\/font><\/strong>. Given they started with a Standard Deviation<\/font><\/strong> =<\/font><\/strong> ~11<\/font><\/strong>, 1.72<\/font><\/strong> has to be wrong. As I scratched my head in confusion and pondered, I noticed these references below the abstract on PubMed: <\/div>\n