Only relatively higher and lower Li+ ratio might predict clinical responses.
OBJECTIVE
To revisit the controversial issue regarding any possible relationship between Li+ ratio and clinical response with a view to explaining the contradictory reports on the subject.


METHODS
Analysis of Li+ ratio and clinical response in 98 bipolar patients. The patients selected in this study were based on the following criteria: (i) fulfilment of DSM-III-R criteria for bipolar disorder; (ii) indication for long-term lithium therapy; (iii) continued lithium therapy for at least 2years; (iv) had data on lithium ratio. Clinical responses were classified into good responders and poor responders (partial responder +nonresponder).


RESULTS
High lithium ratio (> or = 0.50) was associated with better clinical response (chi2 =5.80, d.f.=1, P< 0.05). In a further analysis, subjects with lithium ratios in the range (mean +1SD) or (0.50-0.67) and mean - 1SD or (0.32-0.49) showed the highest and lowest response rates. However, lithium ratios lower than 0.32 appear to be associated with a high response rate.


CONCLUSIONS
The inconsistent results concerning the association between lithium ratio and clinical response reported since the 1970s may have been at least partially due or related to the inadequate inclusion of extreme lithium ratio data. However, this hypothesis needs to be tested in a larger, prospective study.
Yang
Y Y
YY
Department of Psychiatry, Chang Gung Memorial, Hospital and Chang Gung University, Taipei, Taiwan. yyyang@adm.cgmh.com.tw
Hu
W H
WH
D001714:Bipolar Disorder / Q000097:blood / Q000188:drug therapy*; D004305:Dose-Response Relationship, Drug; D005260:Female; D006801:Humans; D008094:Lithium / Q000097:blood* / Q000627:therapeutic use*; D008297:Male; D012737:Sex Factors; D016896:Treatment Outcome
D008094:Lithium