When someone is truly suicidal and not just saying it to get the attention he needs, all bets are off for us amateurs. At that point, medication is necessary because a quick fix is necessary to stabilize the person before he does commit suicide. Normally, none of these drugs are particularly good for a 15 year old and were never approved for use for them, as the brain is not yet fully developed. But some do get to a point where only medication is going to work quickly enough to stop the deterioration in mood. As for your feeling it's not working, you don't say how long he's been on the meds -- they can take 4-6 weeks to start working, but the side effects start right away. If your son was depressed enough to be suicidal before starting medication, then it's hard to see how the medication could be causing it unless you see changes in behavior and mood since he started them that is different in kind and intensity from what he was feeling before starting them. It can take time and trial and error to find a drug that works. As for this combination, trazadone is very sedating, while Pristiq is known for being stimulating. Because both affect serotonin, there can be some people who suffer from too much targeting of the same neurotransmitter with different drugs. Trazadone is so sedating it's often used for its side effect to help people sleep. The main thing is, if it's not working, or if he's too sedated, then these might not be the best drugs, or the combination might not be the right thing for him. These are things to talk to his psychiatrist about-- if his psychiatrist isn't told he's not having the desired benefit, and very often patients don't tell their docs, then he can't respond to it. But be careful about abrupt changes -- these drugs can be hard to stop taking and sometimes you get a doctor who doesn't pay heed to this. Best of luck.