Platelet serotonin levels support depression scores for women with postpartum depression.
OBJECTIVE
It is very challenging to make an unbiased diagnosis of psychiatric illness. Platelets have long been proposed as easily obtainable, neurological models of serotonergic neurons. This study examined whether a new measurement for platelet serotonin could aid in the diagnosis of postpartum depression and support the results from questionnaires.


METHODS
Study participants included 11 patients with postpartum clinical depression according to the Diagnostic and Statistical Manual of Mental Disorders, fourth edition, criteria. Blood was donated either at acute onset of depression before treatment (n = 5) or while patients were nonresponsive to paroxetine treatment (n = 8; 2 of these patients dropped out). A follow-up sample was donated approximately 8 weeks later during paroxetine treatment (n = 11). Platelet serotonin was determined with a new immunocytochemical assay and standard high-pressure liquid chromatography. Serotonin levels were compared with Hamilton Depression Rating Scale scores.


RESULTS
Platelet serotonin levels in patients with depression before paroxetine treatment or nonresponsive to their initial paroxetine regimen were reduced to 50% of normal levels. Treatment-induced severe reduction of platelet-associated serotonin only occurred in responsive patients. Mean platelet serotonin levels were significantly lower in responders (17.3%, standard deviation [SD] 4%), compared with nonresponders (33.4%, SD 8%; p < 0.001).


CONCLUSIONS
Platelet serotonin levels obtained with a new immunocytochemical test correlated well with results from depression scoring and might be useful as evidence-based support for questionnaires.
Maurer-Spurej
Elisabeth
E
Canadian Blood Services, Department of Pathology & Laboratory Medicine, University of British Columbia, Vancouver, BC, Canada. emaurer@interchange.ubc.ca
Pittendreigh
Cheryl
C
Misri
Shaila
S
D000328:Adult; D001792:Blood Platelets / Q000378:metabolism*; D002851:Chromatography, High Pressure Liquid; D019052:Depression, Postpartum / Q000097:blood* / Q000175:diagnosis / Q000523:psychology*; D003866:Depressive Disorder / Q000175:diagnosis / Q000523:psychology*; D005260:Female; D005455:Fluorescent Antibody Technique; D006801:Humans; D011569:Psychiatric Status Rating Scales; D012701:Serotonin / Q000097:blood*; D011795:Surveys and Questionnaires
D012701:Serotonin