"Since the late 1990s, the US policy has linked its counternarcotics policy with counterterrorism policy in Afghanistan. However, there is modest proof of a direct involvement by Al Qaida in the international drug trafficking network. The 9-11 Commission found little evidence to confirm this accusation. Groups known to be involved in the illicit drug economy were rather the Sunni Hizb-i Islami group of Gulbuddin Hekmatyar and the Taliban. [37] However, according to the World Bank and UNODC, the Taliban derived more income and foreign exchange in the period 1996-2000 from taxing smuggled goods from Dubai to Pakistan than from the drug industry. Even now, the Taliban have several sources of income and they are not economically dependent on the narcotics trade only. [38] This reality, however, has not stopped the United Nations Office on Drugs and Crime to argue that “fighting drug trafficking equals fighting terrorism”.[39]"

Source

Corti, Daniela and Swain, Ashok, "War on Drugs and War on Terror: Case of Afghanistan," Peace and Conflict Review (San Jose, Costa Rica: University for Peace, 2009) Volume 3, Issue 2, p. 5.
http://www.review.upeace.org/…