@anamur-- Have you spoken to your doctor about this? I don't think you should replace your medication with a supplement.
5-HTP definitely has benefits for anxiety and depression. It can increase the amount of serotonin circulating in the brain, reducing anxiety symptoms. But it's not a medication and it's not meant to treat any condition.
You have to ask your doctor and if your doctor approves, you have to switch under close supervision. SSRI medications can remain in the system for a long time and it will certainly cause withdrawal effects. Switching to 5-HTP suddenly can cause serious problems for you. You might experience mood changes, anxiety attacks and perhaps even suicidal tendencies because of a chemical imbalance.
Just because something is naturally produced by the body and is called a supplement doesn't mean that it can be taken liberally. You have to be careful with 5-HTP.