My 29 year old daughter is having what she says is like shock or lighting waves in her head all the time.  She is active in drugs. She will sometimes stand up and everything will go black and her legs with start shaking. I am very concerned because she has stated this is happening what could be wrong?
Sounds like this is a blood pressure problem called orthostatic.  This can be diagnosed by taking a blood pressure reading laying down and then one after immediately standing.  If the blood pressure Chat Doctor.  The hard part is then figuring out what is causing it.  There are good treatments for this condition, but she should see a doctor. In the meantime when she starts to feel dizzy tell her to do toe raises or cross her legs to increase blood flow to her heart.  This should help temporarily. Hope this helps