Onset of antidepressant action: a pharmacological question?
OBJECTIVE
This study was conducted to analyse the onset of action of antidepressants in naturalistic conditions.


METHODS
Multicenter, prospective, open-label, non-comparative naturalistic study among 582 depressed outpatients treated with mirtazapine. The patients were assessed at screening, and after 1, 2 and 4 weeks by the 17-item Hamilton depression rating scale (17-HAM-D) and clinical global impression (CGI). Onset of action was measured by traditional analyses based on the time to a persistent reduction of more than 50% from baseline on the 17-HAM-D. Patients were grouped into four groups: very fast responders, fast responders, traditional responders and partial or non-responders. The non-parametric Kruskall-Wallis test was used to assess differences between the groups and logistic regression to predict response after 1 week of treatment.


RESULTS
16% of patients had a very fast response, 42.1% a fast response, 26.5% a traditional response and 15.5% a partial or non-response. There were no significant differences between these groups with regard to dose of mirtazapine or sociodemographic characteristics. The baseline total 17-HAM-D was lower in the faster groups than in the slower groups. The evolution of 17-HAM-D items was similar in each responder group.


CONCLUSIONS
Time to response varied from early faster response to late slower response. The evolution of 17-HAM-D for each type of response was similar, but occurred at a different time in each group.
Rojo
J E
JE
Psychiatry Department, Hospital Universitari de Bellvitge, L'Hospitalet de Llobregat, Barcelona, Spain. jrojo@csub.scs.es
Gibert
K
K
Cobo
J
J
Rodriguez-Cano
E
E
Vallejo
J
J
D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000929:Antidepressive Agents, Tricyclic / Q000627:therapeutic use*; D003866:Depressive Disorder / Q000188:drug therapy* / Q000523:psychology; D005260:Female; D006801:Humans; D008297:Male; D008803:Mianserin / Q000031:analogs & derivatives* / Q000627:therapeutic use; D008875:Middle Aged; D000078785:Mirtazapine; D011446:Prospective Studies; D013997:Time Factors
D000929:Antidepressive Agents, Tricyclic; D008803:Mianserin; D000078785:Mirtazapine