Opiates are insanely physically addictive and you can easily accidentally become addicted to them using them as prescribed, hence all the lawsuits.
Well lucky for you, I didn't make that claim!
Notably this study predated the addition of compulsive sexual behavior disorder to ICD-11 and was neither validated nor accepted as the correct model (hence excessive use of 'proposed' and 'preliminary'). You may also notice there are seven separate commentaries in response to this study with an eighth by the original authors in which they acknowledge the several limitations of their proposed model[1] and make the following statement:
"Rather than present an argument against CSBD, it is our intention and belief that our model of PPMI adds needed nuance to ensure the accurate use of the CSBD diagnosis."
[0] https://link.springer.com/article/10.1007/s10508-018-1248-x
[1] https://link.springer.com/article/10.1007/s10508-019-1406-9