Creatine Monohydrate as Adjuvant Therapy for Bipolar Depression

Inclusion Criteria: * Individuals eligible for the study will be adults aged 18 to 60 years of age who met DSM-IV criteria assessed by the SCID (Structural Clinical Interview for DSM-IV) for type I bipolar disorder, current episode depressed. * Patients who have scored \> 19 on the Montgomery-Asberg Depression Rating Scale (MADRS) will be included, although more than two weeks of treatment with lithium (serum level\> 0.8 mEq / L), valproate (serum levels\> 50 mg / L) or quetiapine (300-600mg/dia dose) or drug combination. * Antipsychotics, anticonvulsants, benzodiazepines, and thyroid supplementation will be allowed if the dose has remained stable over the past two weeks. * Antidepressants will be allowed if the dosage has remained stable for 4 weeks. Exclusion Criteria: * Subjects with substance abuse within 2 weeks before inclusion or substance dependence up to 2 months will not be included. * Other exclusion criteria will be: * diagnosis of schizophrenia, * dementia, * delirium, * epilepsy, * mental retardation, * clinically unstable medical illnesses, * preexisting renal disease, * history of hypersensibility to creatine. * Not included are individuals at high risk for suicidal or homicidal behavior or self-mutilation will not be included. * Women with gestational potential can only be included if they are using reliable contraception.