Inclusion Criteria:

A subject will be eligible for inclusion in this study only if all of the following criteria apply:

• completed 32 weeks of open label treatment in study SCA101469 and, in the investigators opinion, has responded to lamotrigine therapy
• male or female subject

A female is eligible to enter and participate in this study if she is of:

1. non-childbearing potential (i.e., physiologically incapable of becoming pregnant, including any female who is post-menopausal or sterilised) or,

2. child-bearing potential, has a negative urine pregnancy test at screening, and agrees to one of the following contraceptive methods:

   • Complete abstinence from intercourse from 2 weeks prior to administration of the study drug, throughout the study, and for a time interval after completion of premature discontinuation from the study to account for elimination of the investigational drug (a minimum of 5 half-lives or longer if the pharmacodynamic profile of the investigational drug warrants a longer time period); or,
   • Sterilisation of male partner; or,
   • Implants of levonorgestrel; or,
   • Injectable progestogen; or,
   • Oral contraceptive (combined or progestogen only); or,
   • Any intrauterine device (IUD) with published data showing that the lowest expected failure rate is less than 1% per year (not all IUDs meet this criterion); or,
   • Any other methods with published data showing that the lowest expected failure rate for that method is less than 1% per year; or,

   • Barrier method only if used in combination with any of the above acceptable methods.

     • willing and able to give written informed consent to participate in the study.

Exclusion Criteria:

A subject will not be eligible for inclusion in this study if any of the following criteria apply:

• subject experienced a 'mood episode' during participation in study SCA101469, or since completing participation in study SCA101469.
• participation in a clinical drug trial other than SCA101469 within the past 30 days or previous participation in this clinical study
• known hypersensitivity to lamotrigine
• in the investigator's judgement, the subject poses a current serious suicidal or homicidal risk, or has made a suicide attempt within the past 6 months.
• combination of carbamazepine and valproate
• concurrent lamotrigine therapy, other than that commenced in study SCA101469
• current or history of substance abuse
• diagnosis of epilepsy
• diagnosis or history of an obsessive-compulsive disorder, social phobia, or eating disorder
• significant cardiac, renal, cerebrovascular, or hepatic condition; no significant abnormalities in the laboratory tests or ECG recording performed during study SCA101469.
• unable to understand or implement instructions
• unresolved drug related adverse event or serious adverse event occurring in study SCA101469