• To determine the total and local gray matter volumes, and N-acetyl aspartate (NAA) levels in patients with bipolar disorders who are within euthimic, depressive or manic/hypomanic period and who are not taking drug;
• To investigate the neuroprotective effects of long-term (6 weeks) use of valproate on total and local gray matter volumes and NAA levels.
• To measure the brain electrical response to visual and auditory impulses before and after valproate treatment in patients within euthimic, depressive or manic/hypomanic period and who are not taking drug, and to compare the data with each other and with normal groups.
• To determine the cognitive functions before and after the valproate treatment in the same patient group, to compare the data with each other and with age- and sex-paired normal controls;
• To determine the relationship between these effects of valproate and clinical improvement;
• To investigate the relationship between cognitive ability status and electrical activity of brain, to compare this with that in control group; to determine the relationship between the data and brain imaging (MRI/MRS) findings in conjunction with localization

Inclusion Criteria:

• diagnosis of type I or II bipolar disorder according to DSM-IV after stratified SCID I interview,
• being currently euthimic (for at least one month), manic-hypomanic and having YMRS points of 15 or more, or being in depressive episode and having HAM-D21 points of 15 or more
• being not taking drugs for at least two weeks before participating in the study (except benzodiazepins)

Exclusion Criteria:

• female who are pregnant or planning to be pregnant, nursing
• having known hypersensitivity to study drug
• being given any psychotropic agent other than benzodiazepine within the last two weeks
• active sustance or alcohol usage within the last two weeks, or substance addiction other than cafein or nicotine (within the last month)
• having another axis I disorder such as comorbid dementia, delirium, obsessive compulsive disorder, eating disorder
• having unstabilised hepatic or renal disorder, thyroid or blood disease
• having history of cerebral surgery
• existence of a degenerative neurologic disease or epilepsy
• having pacemaker
• having a prosthesis able to magnetic effect in eye, brain or sites near to these regions
• homicide thougths or severe catatonia required to be hospitalized
• having mixed episode

The above information is not intended to contain all considerations relevant to a patient's potential participation in a clinical trial.