qualitative research

What is the impact in USA of your selected topic (substance abuse) as a burden disease. 
When appraising qualitative research, why is the concept of data saturation important? 
what are the benefit and the limitation of qualitative research?  
Instructions:
Use an APA style and a minimum of 200 words. Provide support from  scholarly sources. The scholarly source needs to be: 1) evidence-based, 2) scholarly in nature, 3) Sources should be no more than five years old (published within the last 5 year), and 4) an in-text citation. citations and references are included when information is summarized/synthesized and/or direct quotes are used, in which APA 7 style standards apply. 
• Textbooks are not considered scholarly sources. 
• Wikipedia, Wikis, .com website or blogs should not be used.