This is a 6 week, randomized, open-label, parallel group study in patients with Bipolar-I disorder (manic depression), who are in remission from an episode. Participants who show cognitive impairment at baseline will be randomized to receive open-label Lurasidone added on to their current medication(s) or continue their usual treatment for 6 weeks. Participants will have 3 clinical visits and 2 telephone appointments during the study. Given the preliminary evidence for efficacy of Lurasidone in improving cognition in schizophrenia, we propose to examine the efficacy of Lurasidone in improving cognition in bipolar patients.

Inclusion Criteria:

1. All patients must be taking either lithium or valproate or one of the atypical antipsychotics for mood stabilization.
2. Patients who show cognitive impairments (-0.25 standard deviations (SD) or below) on either the Trail Making Test- trial B (TMT-B) or California Verbal Learning Test (CVLT) trials 1 to 5, or CVLT long delay free recall, at baseline visit.
3. Males or females aged 19 to 65 years inclusive.
4. Diagnostic and Statistical Manual IV edition (DSM-IV TR) diagnosis of Bipolar Type I Disorder, with or without a history of psychosis.
5. Clinically stable with a Montgomery Asberg Depression Rating Scale (MADRS) and Young Mania Rating Scale (YMRS) score less than or equal to 8.
6. A sufficient level of English using a language screening questionnaire.
7. Capability of understanding, consenting to, and complying with the requirements of the study.

Exclusion Criteria:

1. A history of unstable or inadequately treated medical illnesses, including moderate to severe brain injury, or neurological illnesses impacting cognitive function.
2. Treatment with Electroconvulsive Therapy (ECT) within eight weeks prior to enrolment; or treatment with an experimental drug within 30 days prior to enrolment.
3. Axis I diagnosis of substance abuse or dependence within the past month.
4. Significant risk of harm to self or others, in the opinion of the investigator.
5. Pregnancy or lactation in female subjects.
6. Liver function tests (AST and ALT) three times the upper limit of normal. -