This study is testing a medicine called Cannabidiol Oral Solution (CBD-OS) to see if it helps people aged 12 to 75 with focal-onset seizures. Focal-onset seizures start in one area of the brain and can cause symptoms like twitching or confusion. The study will look at how well CBD-OS works and if it's safe. CBD-OS is already used to help other kinds of seizures, but this study is to see if it helps focal seizures too. Some people in the study will also have special tests like brain scans (fMRI) and memory tests. These tests will help doctors understand how the treatment affects the brain.

• Participants need to have focal epilepsy and be on 1 to 4 stable seizure medicines.
• People with certain health issues or who use cannabis products can't join.
• The study includes multiple visits and tests, but no cannabis use is allowed during the study.