Cannabis, popularly known as Marijuana in Nigeria was the most widely used substance in Nigeria, followed by tramadol, codeine or morphine and cough syrups containing codeine or dextromethorphan
The report also states that those with a high risk of drug users account for 0.4% of the population, about 376,000 people. NBS says the project aims to support Nigeria in fighting drug production, trafficking and use and improved access to quality drug prevention, treatment and care services.
In Nigeria, 14.3 million people of the total population made use of the various form of hard drugs, excluding alcohol and tobacco-related products. This figure represents 14% of the country's population between the age of 15 and 64 in the year 2017.

This was revealed by National Bureau of Statistics (NBS) in its report, Drug Use in Nigeria 2018 Survey released on Tuesday, January 30, 2019.

The report, the first in Nigeria was conducted in collaboration with the Centre for Research and Information on Substance Abuse (CRISA) with technical support from the United Nations Office on Drugs and Crime (UNODC). It was funded by the European Union (EU) under the 10th European Development Fund (EDF)

Titled, “Response to Drugs and Related Organised Crime in Nigeria,” the report estimates people who had used a drug at least once in the past 12 months as well as high-risk drug users.

NBS says the project aims to support Nigeria in fighting drug production, trafficking and use and improved access to quality drug prevention, treatment and care services.

According to the NBS report, Cannabis, popularly known as Marijuana in Nigeria, “was the most widely used substance in the past year in Nigeria, followed by pharmaceutical opioids (mainly tramadol, and to lesser extent codeine or morphine) and cough syrups containing codeine or dextromethorphan.”

The report also states that those with a high risk of drug users account for 0.4% of the population, about 376,000 people.

Here is the extent of drug use in Nigeria:

Any drug use - 14,300,000
Cannabis - 10,640,000
Opiods - 4,610,000
Heroin - 87,000
Pharmaceutical Opioids (Tramadol. Codeine, Morphine) - 4,608,000
Cocaine - 92,000
Tranquillisers/Sedatives - 481,000
Cough Syrups - 2,360,000

Source: https://www.collinsuchendusblog.com/2019/01/hard-drug-users-in-nigeria-rise-to-143.html?m=1

Hmmm ... I believe the north accounts for a good percentage of that figure. God help this generation.