• Use of psychoactive substances is a complex phenomenon. While certain substances are 'legal' and have more social acceptance (such as tobacco, alcohol, and to some extent, cannabis), use of others (such as opioids, stimulants, etc.) attracts both legal and social sanction and hence, remains a relatively hidden phenomenon. Thus, a single methodological approach will be insufficient to study this multifaceted phenomenon in a large and diverse country like India. Consequently, NDUS uses a combination of different methodological approaches to study the drug use situation India and provide precise estimates for the prevalence of use of various psychoactive substances in the country.
• The methodological approaches being employed in NDUS are:

• A Household Sample (HSS) Survey in a representative sample of the general population to determine the proportion of people who use substances and people who are suffering from substance use disorders. The HHS survey is being carried out in about 185 districts of the country spread across all states and UTs and includes both males and females and entire population between the ages of 10 and 75 years. Nationally, the HHS survey will cover more than 1,50,000 households and about 6,00,000 individuals will be interviewed.
• A Respondent Driven Sampling (RDS) Survey (with multiplier) among drug dependent individuals to determine the number of individuals dependent on various illicit substances. This RDS survey is being carried out in about 120 districts of the country and include male and female drug users above the age of 18 years. Nationally, the RDS survey will include interviews of more than 60,000 drug using individuals.
• Focused Thematic Studies: NDUS includes 9 in-depth studies on specific themes and population sub-groups:
  • 1) Substance Use among Prison population;
  • 2) Substance Use among Homeless populations;
  • 3) Substance Use among Hijra / Transgender communities;
  • 4) Substance Use among Female sex workers;
  • 5) Substance Use among Transport workers;
  • 6) Use of Newer psychoactive substances;
  • 7) Use of Indigenous psychoactive substances;
  • 8) Substance use treatment experience survey;
  • 9) Substance Use among Students.

• An online Survey among service providers to explore the availability of treatment services for substance users in the country and study the extent and pattern of service utilization and gaps thereof.
• The findings from the abovementioned survey methodologies will be collated to generate the national and state-level estimates for substance use disorders and to provide information on the profile of substance using individuals and the pattern of substance use.