I'm not sure, but that is a good question. I tend to think that the data sources could count the same individual multiple times because the report ("2019-methodological-summary-and-definitions") says so:
> An important issue for users of NSDUH and TEDS data to consider is that the unit of analysis for TEDS is admissions to substance use treatment, whereas NSDUH estimates are for individuals who received substance use treatment. Consequently, individuals who were admitted to substance use treatment multiple times in the reporting period would be counted more than once in the TEDS admissions data.
Earlier in that same document, the authors state that they only ask these two categories about suicidal thoughts:
- the individual is over 18
- the individual is under or over 18, but has had a major depressive episode (MDE)
The statistics also include multiple studies with variable sampling beyond NSDUH and TEDS. I think the best one can do is to presume mixed data, which would indeed include repeat attempts for the same individual.