Figure 4

(a) In susceptible users’ fraction stochastic Runge–Kutta method converges to drug-free equilibrium, while deterministic solution is the mean of stochastic Runge–Kutta method solution for \(\mathrm{h}=0.01\). (b) In susceptible users’ fraction stochastic Runge–Kutta method solution is unbound for drug-free equilibrium for \(\mathrm{h}=0.01\). (c) In drug users’ fraction stochastic Runge–Kutta method converges to drug-present equilibrium, while deterministic solution is the mean of stochastic Runge–Kutta method solution for \(\mathrm{h}=0.01\). (d) In drug users fraction stochastic Runge–Kutta method shows failure of dynamical properties for drug-present equilibrium for \(\mathrm{h}=6\)