It is even worse because the participants in the survey were not randomly selected. They instead must choose to visit the Sapiens Labs website to complete the survey. Taking the survey is encouraged through advertising.
I can't say for certain but I imagine that voluntarily visiting a website to complete a mental health survey might appeal more to those with mental health issues thus skewing the data. Also you may have some people that visit to purposely give false data. Very much not unheard of in internet polls. I have no real idea how much either of these have affected the data but it makes me very suspect of the data. If you can't trust the data you can't trust any studies based upon it.
I can't say for certain but I imagine that voluntarily visiting a website to complete a mental health survey might appeal more to those with mental health issues thus skewing the data. Also you may have some people that visit to purposely give false data. Very much not unheard of in internet polls. I have no real idea how much either of these have affected the data but it makes me very suspect of the data. If you can't trust the data you can't trust any studies based upon it.