Pharmacy SMS, Take n GO Vs Return the pills

As healthcare costs soar, the Health Ministry has found that a substantial amount of medicine dispensed by government hospitals goes unused or expired. Through its "return medication programme" implemented last year, the ministry now wants to find out more about the causes of this waste and reduce it.

The question was:
1. Why there were unused pills eventhough the pharmacy/doctors have accurately advice the patients to finish the medicine?

If the ministry to find more about the causes of this waste, should be or probability by:
1. The patients average ages 20-30 years might be take only once or twice of the pills and immediately make them fully recover. Even so, they have to finish their medicine accordingly because the disease might be not totally dissolved from their body. For example; They have to take 8 pills to fully recover but only half from the amount only taken. So, 4 pills were wasted.
2. The awareness of natural cure-herbal, traditional..etc..