The genesight test specifically test for how your body would metabolize depression/anxiety and ADHD meds.
For example, if you are a poor metabolize of a drug, you would be more likely to have side effects. And if you are a hyper metabolize you wouldn't respond as well to normal doses as you would break down and clear the drug faster that the average person.
Both of these issues would eventually show up through trial and error with dose adjustment over the corse of a year or so, however with the genetic testing you can get that information in a couple of weeks and avoid a lot of the back and forth with does and drug changes.
Pharmacist here with a couple suggestions to make your life easier.