Abstract
Background:
Optimal treatments for bipolar depression, and the relative value of specific drugs
for that purpose, remain uncertain, including agents other than antidepressants.
Methods:
We searched for reports of placebo-controlled, monotherapy trials of mood-stabilizing
anticonvulsants, second-generation antipsychotics, or lithium for acute major depressive
episodes in patients diagnosed with type I or II bipolar disorder and applied random-effects
meta-analysis to evaluate their efficacy, comparing outcomes based on standardized
mean drug-placebo differences (SMD) in improvement, relative response rates (RR),
and number-needed-to-treat (NNT).
Results:
We identified 24 trials of 10 treatments (lasting 7.5 weeks, with ≥50 collaborating
sites/trial) that met eligibility criteria: lamotrigine (5 trials), quetiapine (5),
valproate (4), 2 each for aripiprazole, olanzapine, ziprasidone, and 1 each for carbamazepine,
lithium, lurasidone, and olanzapine-fluoxetine. Overall, pooled drug-over-placebo
responder-rate superiority (RR) was moderate (29% [CI: 19–40%]), and NNT was 8.2 (CI:
6.4–11). By SMD, apparent efficacy ranked: olanzapine+fluoxetine≥valproate>quetiapine>lurasidone>olanzapine,
aripiprazole, and carbamazepine; ziprasidone was ineffective, and lithium remains
inadequately studied. Notably, drugs were superior to placebo in only 11/24 trials
(5/5 with quetiapine, 2/4 with valproate), and only lamotrigine, quetiapine and valproate
had > 2 trials. Treatment-associated mania-like reactions were uncommon (drugs: 3.7%;
placebo: 4.7%).
Discussion:
Controlled trials of non-antidepressant treatments for bipolar depression remain scarce,
but findings with olanzapine-fluoxetine, lurasidone, quetiapine, and perhaps carbamazepine
and valproate were encouraging; lithium requires adequate testing.
Key words
anticonvulsants - antipsychotics - bipolar depression - controlled-trials - lithium
- meta-analysis