My son accepted when he was younger that we had head boo-boo that we had to take meds for.

Then he wanted to know the real name.

Then he wanted to know what it meant. So I drew a chart. Take a sheet landscape / horizontal fold it in half 2x then open it up. On the top crease draw a line and write happy. On the bottom crease draw a line and write sad. Tell her most people go from happy to sad and draw a wave from one side to the other within the lines. Then take a different marker/ colored pencil/ pen and tell her that you get super happy and sad. Draw a wave line that goes above and below the two lines. Then if you want to/ if she's still interested tell her you take meds to be more like the first line but sometimes drs have to fix them so you have to go to the hospital.

Now I sit down with my son and tell him. "I have to go to the hospital. My meds are messed up and that's the fastest way to fix them."