Table 3. Reasons for Inclusion and Exclusion of Hypothesised Linguistic Features.

Linguistic Feature	Reason for Inclusion/Exclusion
Included
Negative emotiona	Theoretical basis and empirical evidence
Positive emotiona	Theoretical basis and empirical evidence
First-person singular pronouna	Theoretical basis and empirical evidence
Absolutista	Theoretical basis and empirical evidence
Excluded
Causationa	Potentially affected by the study context Potentially reflective of CFS/ME or depression A less conclusive evidence-base Available linguistic data for personality disorder only
Insighta	Potentially reflective of CFS or depression A less conclusive evidence-base Available linguistic data for personality disorder only
Discrepancya	A less conclusive evidence-base Available linguistic data for personality disorder only
Past-focusa	Potentially reflective of CFS or depression Available linguistic data for personality disorder only
Future-focusa	Potentially reflective of CFS or depression Available linguistic data for personality disorder only
Achieveb	Potentially reflective of CFS or depression A lack of previous evidence

Note. Linguistic features were taken from the LIWC2015 (Pennebaker et al., 2015) and absolutist (Al-Mosaiwi & Johnstone, 2018) dictionaries.

^aIdentified deductively.

^bIdentified inductively.