Table 2.

Summary of characteristics of included quantitative publications

Study	Country	Participants	Design	Relevant constructsa	Construct measurements	Outcome(s)	Relevant results
Tang (2015)23	China	N=523 people with DUD Age: ³20 years Sex: 75.9% male Race/ethnicity: 58% Han	Longitudinal In MMT treatment	Perceived social stigma (societal discrimination) Perceived health care provider stigma (MMT discrimination)	Family relationship score Provider–client Relationship score	Retention in MMT treatment	61% of the participants dropped out between baseline and 6-month follow-up. Dropout rates varied by clinic and were related to four factors as follows: family relationships, provider–client relationships, feelings toward MMT, and feelings toward one’s current dosage.
Mak et al. (2017)24	Hong Kong	N=124 people with SUD Age: mean =44.92 years (SD: 12.77) Sex: 76% male	Cross-sectional In recovery at outpatient clinics	Perceived social stigma Perceived health care provider stigma Self-stigma	Discrimination subscale of the stigma scale ISMI items adapted for discrimination from providers Self-stigma scale	Clinical recovery Personal recovery Treatment engagement	Results of structural equation modeling showed that perceived social and health care provider stigma led to more internalized self-stigma and lower engagement with treatment, which in turn led to worsened clinical and personal recovery.
Link et al. (1997)25	United States	N=84 men with mental illness and SUD Age: mean =34 years Sex: 100% men Race/ethnicity: 63% African American, 23% Hispanic, and 14% White Non-Hispanic	Longitudinal In therapeutic community or community residence treatment	Enacted social stigma Perceived social stigma	Experiences of rejection scale Devaluation/discrimination scale	Substance abuse in the past 6 months	Substance abuse in the past 6 months was rare according to both self-report (10.7%) and urinalysis (11%). The majority of men (62%–72%) reported each of several types of perceived social discrimination. Although psychiatric symptoms, including substance abuse, declined over the year of treatment, scores on stigma measures did not change. Furthermore, experiences of rejection explained significant variance in depressive symptoms at follow-up.
Brown et al (2015)26	United States	N=120 people with SUD Age: mean =31.28 years (SD=10.94) Sex: 74% male Race/ethnicity: 90% Caucasian	Cross-sectional In residential treatment	Perceived social stigma Self-stigma	Fear of enacted stigma subscale of the SASSS Self-devaluation subscale of the SASSS	Self-efficacy for substance use abstinence Previous treatment attempts Days in current treatment	Temptation to use (a self-efficacy subscale) was modestly but significantly correlated with both fear of enacted stigma and self-devaluation (r=0.32 and0.24, respectively), while a stigma avoidance subscale was correlated with confidence not to use (another self-efficacy subscale; r=−0.25). The number of previous treatment attempts and days in current treatment were not related to either stigma scale.
Frischknecht et al (2011)27	Germany	N=250 people (106 with SUD, 144 controls) Age: mean =36.3 and 33.8 years (SD=7.8 and 10.1) Sex: 33% and 56% female	Cross-sectional In opioid maintenance treatment or controls	Self-stigma Enacted social stigma Perceived social stigma	Alienation subscale of the ISMI scale Discrimination ISMI subscale Social withdrawal ISMI subscale	Treatment variables	Number of previous rehabilitation attempts, number of rehabilitations completed, number of self-withdrawals, and number of inpatient withdrawals were all unrelated to ISMI scores.
Kulesza et al (2014)28	United States	N=17 people with SUD Age: mean =34.06 years (SD=12.28) Sex: 65% male Race/ethnicity:100% Caucasian	Longitudinal In outpatient treatment	Self-stigma	SASS	Drug or alcohol use at follow-up	After controlling for depressive symptoms, participants who reported more self-stigma at post-treatment reported more days using drugs (but not alcohol) at 1-month follow-up. Baseline self-stigma did not predict follow-up use of either alcohol or drugs after controlling for depressive symptoms. Analysis did not show an effect of measurement time (ie, pre-, post-, or at follow-up of treatment) on self-stigma.
Schomerus et al (2011)29	Germany	N=121 people with AUD Age: mean =46.8 years (SD=8.8) Sex: 79% male	Cross-sectional In detox treatment	Perceived social stigma Self-stigma	Aware subscale of the SSAD scale Apply subscale of the SSAD	Drinking-refusal self-efficacy Years of drinking problems	Aware and Apply subscales were significantly correlated, r=0.32. The Apply subscale was negatively correlated with drinking-refusal self-efficacy, r=−0.34, and associated with more years of drinking problems as well as more depressive symptoms. Apply was not related to greater severity of alcohol dependence. Aware was not related to any outcome variables.
Randles and Tracy (2013)30	Canada	N=105 people with AUD Age: mean =38.7 years (SD=9.6) Sex: 54% female Race/ethnicity:76% Caucasian, 14% first nation, 10% others	Longitudinal In AA treatment	Shame behaviors Guilt-free shame	Non-verbal displays of shame coded from video-recorded interviews State Shame and Guilt Scale	Likelihood of relapse Severity of relapse (number of drinks consumed)	Non-verbal shame behaviors predicted both the likelihood and severity of relapse, as well as increases in distressing psychiatric symptoms. Self-reported guilt-free shame did not predict relapse variables.
Luoma et al. (2014)31	United States	N=103 people with SUD Age: mean =35.5 years (SD=9.62) Sex: 59% male Race/ethnicity: 85% White	Cross-sectional In residential treatment	Self-stigma	ISS ISSA scale	Length of stay in treatment	ISS and ISSA scores were positively correlated (r=0.63). ISSA was also positively correlated with number of days in residential treatment, accounting for 10.6% of the variance in length of stay in the regression equation.
Kamaradova et al (2016)32	Czech Republic	N=332 outpatients (58 with SUD) Age: mean =42.66 years (SD=14.16) Sex: 52% female	Cross-sectional In psychiatric treatment	Stigma (self-stigma, perceived social stigma, and enacted social stigma)	ISMI scale	Treatment adherence	Higher stigma was related to lower treatment adherence and greater disorder severity in the entire sample. Results were not reported for SUD patients alone, though SUD patients did not differ from others in ISMI scores.

Note:

^aConstructs in italics were not actually used by the authors, but were inferred from the content of the discussion.

Abbreviations: AUD, alcohol use disorder; DUD, drug use disorder; ISMI, Internalized Stigma of Mental Illness; ISS, Internalized Shame Scale; ISSA, Internalized Stigma of Substance Abuse; MMT, methadone maintenance therapy; SSAD, Self-Stigma in Alcohol Dependence; SASS, Substance Abuse Stigma Scale; SASSS, Substance Abuse Self-Stigma Scale; SUD, substance use disorder.