Deciding on a topic might seem easy but once you begin to look for research and reports you might find that you have to broaden or narrow some aspect of the topic you have chosen.
Are you interested in a particular population group? Why? I ask this because at times the literature does not cover that group in the way you might hope. Do you know that it is a group that is being studied? Age and race may not have been a primary focus for one area of research but could be included in studies. You may have to broaden your focus. Or at times, make it more specific or narrow.
What else might also have been researched along with your topic that could be adding to the results? For instance HIV is a known negative effect of IV drug use. If you are getting too many or too little results change the strategy. Are there organizations that have your topic as their primary focus? What publications do they have?
Use the tools you have access to. What do they provide? Google is a great way to find organization and associations but not for article searching. Databases are structured and transparent. You can identify all that is included and use the filters and features to focus your results.
Finding articles is where you begin to focus in on aspects of the condition/major topic you are researching.
Alcohol and drug information might be covered in publications that target healthcare providers or ones for social services.
The focus you take will direct which database you choose.
Addiction will be covered in a variety of sources.
What I mean by subject term is that the database has created a term/phrase that they use as the primary one for the many variant terms authors may use that essentially means the same thing. This is how the database assists in making sure you don't miss anything. It is also a reason you should always think of synonyms and other ways an author may have written on your subject.
Proquest Social Science Database includes more than journal articles so make sure you narrow your results if scholarly articles is all you want. A new addition is Proquest's Public Health Database, which covers all the interdisciplinary areas of public health.
What do you know about the disease or condition? Historical, causes, etc. Typically background information can be found in texts or web sources. Titles may include words like Basics, Overview, Introduction or something similar. Substance abuse can include alcohol, drugs and smoking. Drugs can be legal or illegal.
MedlinePlus page on Drug Use and Addiction
you might be interested in Alcohol Use Disorder (AUD)
A publication Preventing Drug Use Among Children and Adolescents links to a pdf- [note cite as a book]
Articles may report on the use of data and/or summarize data that the researchers collected. Use the articles to get information on specific data. If it is held by an organization see if you can find that.
National and state data are often on the web free of charge but may only provide a summary.
CDC- the CDC has many depts and a variety of types of information on their site. It can be difficult to navigate at times.
If you use Google for what it does best, you can get to some areas of the site. Here are some examples
Alcohol and Substance Misuse (within Workplace Health Promotion)
Pay attention to the section of the CDC site you are on. What division is it? What category/section is it in. You may want to move one way or the other within that section.