The model parameters are described as Λ (denotes the individuals entering the susceptible population from general population), μ (denotes the general population natural decease rate), δ1 (denotes the removal rate due to drug related deaths of users not in treatment and the recovery rate of those who stop using drugs without treatment), δ2 (denotes the removal rate due to drug related deaths of users in treatment and the lucky cure rate that leads to drug-free life accompanied by immunity to drug addiction in the time period of modeling), β1 (denotes the probability of becoming a drug user), p (denotes the drug users who get treatment), and β3 (denotes the probability of a drug user in treatment relapsing to untreated use).