Medication is certainly required for some mental conditions. Take for instance, a condition like Alzheimer's disease, a person with this condition is known to have hormonal imbalances and the best way to tackle such problem is to provide medications for such a person.
However, there are some mental illnesses that not only medication is needed as treatment. Some one with depression needs more than tablets, counseling and self development programs will be of greater benefits to such person.
Keep in mind that there are other treatment options for certain someone with mental illness. Example is Electroconvulsive therapy (ECT).
There are some people who are mentally ill who are required to take certain medications to help them cope better. The drugs will allow their minds to be clearer so that they can function almost normally. They can forget about the triggers that are causing them to feel unstable even for a short while.
As a person slowly recovers, the amount of medications that the person takes also becomes lesser. For instance, if a person needed to take 2 tablets of one drug a day, it may be reduced to one tablet, then a half tablet until such time when the medication is not needed anymore.