Table 1 Inclusion criteria

Inclusion was possible if the patient:

 1) was either officially diagnosed with the DSM-V classification severe ‘substance use disorder’ or informally assessed as such. A patient could either be still an active user, recently quit or in remission of alcohol, cannabis, cocaine, opioids (including heroin), sedatives and/or gamma-hydroxybutyric acid (GHB);

 2) had a serious non-reversible, life-threatening somatic disease or was suffering from progressive, severe physical deterioration as a result of active addictive behaviour without the prospect of cure;

 3) was 18 years or older;

 4) had mastered Dutch in such way that it allowed him/her to participate in an interview;

 5) was cognitively capable enough to answer interview questions (due to SUD, many patients are cognitively damaged);

 6) understood what the study meant for him/her.

Furthermore, the recruiting professional caregiver:

 7) had to answer the following question with ‘no’: “would it surprise you if this patient would die within five years?” [43];

 8) had explicitly communicated with the patient about the fact that (s) he was not going to be cured and now reached a palliative phase.