single-agent and adjunctive treatments. Antidepressant effectiveness varies, which may be related to different serotonergic and dopaminergic receptor binding profiles. Quetiapine and the combination of olanzapine and fluoxetine have both demonstrated effectiveness in bipolar depression. In light of recent evidence, olanzapine (Zyprexa) has been FDA approved as an effective monotherapy for the maintenance of bipolar disorder. A head-to-head randomized control trial in 2005 has also shown olanzapine monotherapy to be just as effective and safe as lithium in prophylaxis. The atypical antipsychotics differ somewhat in side effect profiles, but most have some risk of sedation, weight gain, and extrapyramidal symptoms (including tremor, stiffness, and restlessness). They may also increase the risk of metabolic syndrome, so metabolic monitoring should be performed regularly, including checks of serum cholesterol, triglycerides, and glucose, weight, blood pressure, and waist circumference. Taking antipsychotics for long periods or at high doses can also cause tardive dyskinesia — a sometimes incurable neurological disorder resulting in involuntary, repetitive body movements. The risk of tardive dyskinesia appears to be lower in second-generation antipsychotics than in first-generation antipsychotics but as with first-generation drugs, increases with time spent on medications and in older patients. New treatments A variety of other agents have been tried in bipolar disorder, including benzodiazepines, calcium channel blockers, L-methylfolate, and thyroid hormone. Modafinil (Provigil) and Pramipexole (Mirapex) have been suggested for treating cognitive dysfunction associated with bipolar depression, but evidence supporting their use is quite limited. In addition riluzole, a glutamatergic drug used in ALS has been studied as an adjunct or monotherapy treatment in bipolar depression, with mixed and inconsistent results. The selective estrogen receptor modulator medication tamoxifen has shown rapid and robust efficacy treating acute mania in bipolar patients. This action is likely due not to tamoxifen's estrogen-modulating properties, but due to its secondary action as an inhibitor of protein Kinase C. Cognitive effects of mood stabilizers Bipolar patients taking antipsychotics have lower scores on tests of memory and full-scale IQ than patients taking other mood stabilisers. Use of both typical and atypical antipsychotics is associated with risk of cognitive impairment, but the risk is higher for antipsychotics with more sedating effects. Among bipolar patients taking anticonvulsants, those on lamotrigine have a better cognitive profile than those on carbamazepine, valproate, topiramate, and zonisamide. Although decreased verbal memory and slowed psychomotor speed are common side effects of lithium use these side effects usually disappear after discontinuation of lithium.