Table 2.

Estimated parameters for model (2)

Parameters	Descriptions	Values	Sources
$\mu$	Natural death rate	1/77	Assumed
$\alpha$	Contact rate of the addicted users	0.553277	Fitted
$\beta$	Contact rate of the professional users	0.008748	Fitted
${\xi }_1$	Transfer rate from E to I	0.131643	Fitted
${\xi }_2$	Transfer rate from E to P	0.017532	Fitted
$v_1$	Transfer rate from I to P	0.000340	Fitted
$v_2$	Percentage of people who temporarily quit in I	0.097332	Fitted
$v_3$	Percentage of people who quit permanently in I	0.040456	Fitted
$w_1$	Percentage of people who temporarily quit in P	0.002685	Fitted
$w_2$	Percentage of people who quit permanently in P	0.220441	Fitted
${\delta }_1$	Recurrence rate	0.252144	Fitted
${\delta }_2$	Percentage of people who quit permanently in $Q_1$	0.130325	Fitted