Table A1.

Adaptation of DSM-5 SUD symptoms to NSSI, present study

Diagnostic and Statistical Manual 5 (DSM-5) Substance Use Disorder (APA, 2013)	Present study	Notes
Important social, recreational, or occupational activities are reduced or given up because of the use of the substance.	Important social, recreational, or occupational activities are reduced or given up because of NSSI.
The substance is often taken in larger amounts or over a longer period than was intended.	Acts of NSSI are often deeper (in the case of cutting), more severe, or occur more often than was intended.
Persistent desire or unsuccessful efforts to cut down or control the use of the substance.	Persistent desire or unsuccessful efforts to cut down or control NSSI.
Recurrent substance use in situations in which it is physically hazardous.	Recurrent NSSI in situations in which it is physically hazardous.	Coders were instructed to select this criterion when NSSI was particularly dangerous or severe: specifically, NSSI that required medical attention (whether or not it was sought by the user), resulted in infection, or, in the case of cutting, reached a depth that would result in permanent scarring.
The substance use is continued despite knowledge of having a persistent or recurrent physical or psychological problem that is likely to have been caused or exacerbated by the use of the substance.	NSSI is continued despite knowledge of a psychological problem that is likely to have been caused or exacerbated NSSI.	Coders were instructed to select this criterion when users acknowledged NSSI exacerbated an existing mental health concern, led to feelings of guilt or shame, or “just made them feel worse.”
A great deal of time is spent in activities necessary to obtain the substance, use the substance, or recover from its effects.	A great deal of time is spent preparing to self-injure, self-injuring, or recovering from NSSI.
Withdrawal, as manifested by either of the following: (A) the characteristic withdrawal syndrome for the substance; (B) the substance] is taken to relieve or avoid withdrawal symptoms.	Withdrawal, as manifested by recurring physical tension levels when NSSI is discontinued.	NSSI does not have a characteristic withdrawal syndrome. Coders were given an interpretation from Nixon et al. (2002): “tension level reoccurs if NSSI is discontinued,” and instructed to focus on physical sensations of agitation (as opposed to craving, which is would be considered mental/psychological).
Craving, or a strong desire or urge to use the substance.	Craving, or a strong desire or urge to self-injure.
Recurrent substance use resulting in a failure to fulfill major role obligations at work, school, or home.	Recurrent NSSI resulting in a failure to fulfill major role obligations at work, school, or home.
Continued use of the substance despite having persistent or recurrent social or interpersonal problems caused or exacerbated by the effects of the substance.	Continued NSSI despite having persistent or recurrent social or interpersonal problems caused or exacerbated by NSSI.
Tolerance, as defined by either of the following: (A) A need for markedly increased amounts of the substance to achieve intoxication or desired effect; (B) A markedly diminished effect with continued use of the same amount of the substance.	Tolerance, as defined by either of the following: (A) A need for markedly increased severity, frequency, or depth (in the case of cutting) of NSSI to achieve the desired effect; (B) A markedly diminished effect with continued levels of severity, frequency, or depth of NSSI.	Continued NSSI does not lead to physical tolerance. Coders were given an interpretation from Nixon et al. (2002): “NSSI occurs more often and/or the severity has increased [since starting].”

Summary of the 11 DSM-5 SUD criteria and how they were adapted for NSSI to the present study. Notes are provided in cases when the adaptation was less straightforward.