I actually agree drugs are useful for treating mental issues, I just disagree that people need a daily drip-drip-drip of e.g. serotonin or dopamine to function. Drugs can be extremely helpful in treating acute mental issues and helping people "break through" or inoculate themselves against episodes of illness, see e.g. psilocybin, MDMA, ketamine for treatments of e.g. anxiety/depression/PTSD/psychological health in the terminally ill, cluster headaches, etc.

The common thread though is that a single dose of the drug offers long-lasting protection, weeks or months or years. It's not about chemically changing the brain day after day, it's about using neurochemicals to jolt the brain out of a rut. It's about occasionally kickstarting the brain back into normal self-regulation, not using externally supplied chemicals to permanently supplement dysregulation.