Table 1.

Summary of studies evaluating anhedonia in opioid dependent individuals

STUDY AUTHORS	OPIOID SAMPLE	DESIGN	ANHEDONIA MEASURE(S)	OTHER MEASURES	MAIN FINDINGS
Prospective Studies (ordered by most recent)
Lubman et al., 2018	N = 121 DSM-IV criteria for current or past year opioid dependence n=90 on methadone or buprenorphine n=31 opioid abstinent, no medication	Observational; repeated assessment monthly for 6 months following baseline; additional 12-month follow-up	(1) TEPS Anticipatory pleasure Consummatory pleasure	(1) Time-line Follow-back (past month drug use)	TEPS scores increased over time (i.e., reduced anhedonia); subscale scores not reported TEPS decreased (i.e., increased anhedonia) in month after above-average opioid use TEPS did not predict opioid use in subsequent month TEPS increased (i.e., reduced anhedonia) in abstinent group compared to pharmacotherapy group TEPS lower in those prescribed methadone (i.e., greater anhedonia)
Krupitsky et al., 2016	N = 306 DSM-IV criteria for opioid dependence; treatment seeking	Double-blind, 24-week randomized controlled trial: (1) 1000mg naltrexone implant plus oral placebo (2) placebo implant plus 50mg oral naltrexone (3) placebo implant plus oral placebo	(1) CPAS Physical anhedonia (2) CSAS Social anhedonia (3) Ferguson Anhedonia Scale lack of interest lack of pleasure		CPAS, CSAS, and Ferguson Anhedonia Scales decreased over time (i.e., reduced anhedonia) for those who remained in treatment and did not relapse (n = 81) No difference on anhedonia measures between those who dropped out and those who continued medication
Zaaijer et al., 2015	N = 10 DSM-IV opioid dependence; detoxified and heroin-free for 2 weeks	Brain imaging (SPECT) prior to extended-release naltrexone (XRNT) injection and two weeks later; 11 healthy controls underwent SPECT at baseline only	(1) SHAPS Consummatory pleasure	(1) Striatal dopamine transporter (DAT) binding	SHAPS scores did not change between baseline and after 2 weeks of XRNT SHAPS scores did not differ at baseline between detoxified heroin dependent and healthy controls No correlation between DAT binding and SHAPS scores at baseline or follow-up
Cross-Sectional Studies (ordered by most recent)
Garfield et al., 2017	N = 90 Opioid pharmacotherapy group n=55 prescribed methadone n=35 prescribed buprenorphine N = 31 Opioid abstinent group minimum 7- days abstinent; DSM-IV opioid dependence past year	Comparison of self-report questionnaires between opioid pharmacotherapy group, opioid abstinent group, and 33 healthy controls	(1) SHAPS Consummatory pleasure (2) TEPS Anticipatory pleasure Consummatory pleasure	(1) Time-line Follow-back (past month drug use)	SHAPS scores higher (i.e., greater anhedonia) for Opioid pharm group and Opioid abstinent group compared to healthy controls TEPS scores lower (i.e., greater anhedonia) for Opioid pharm group and Opioid abstinent group compared to healthy controls Significant correlations indicating greater illicit opioid use associated with greater anhedonia on SHAPS and TEPS in Opioid pharm group Duration of opioid abstinence not associated with SHAPS or TEPS in Opioid abstinent group
Huhn et al., 2016	N = 36 Prescription Opioid Dependent Patients (POPD); completed medically assisted withdrawal; in residential treatment	Laboratory session included self-report assessment, cue- reactivity task, and affect modulated startle response task; comparison with 10 healthy controls	(1) SHAPS Consummatory pleasure	(1) AMSR startle response (2) fNIRS neural activity	SHAPS scores higher (i.e., greater anhedonia) for POPD compared to healthy controls POPD showed less startle suppression than healthy controls when viewing positive stimuli (i.e., less positive evaluation of stimuli) POPD displayed reduced neural activation to images of positive social interactions compared to healthy controls
Zijlstra, Booij, van den Brink, & Franken, 20081	N = 12 Males only; DSM-IV opioid dependence; in inpatient treatment; abstinent for minimum of 1 week (mean of 5.9 weeks)	Comparison of brain imaging (SPECT) and self-report assessments with 18 healthy controls	(1) SHAPS Consummatory pleasure	(1) Striatal dopamine D2 receptor (D2R) availability	SHAPS scores did not differ between abstinent opioid dependent group and healthy controls No correlation between D2R availability and baseline SHAPS
Pozzi et al., 20081	N = 24 DSM-IV opioid dependence; abstinent at time of study (at least 45 days since end of detox); recruited from self-help groups, day hospital, or therapeutic community **Same sample as Janiri et al 2005	Comparison of self-report and interview-based assessments with 22 alcohol dependent and 24 multidrug dependent individuals	(1) SHAPS Consummatory pleasure (2) SANS anhedonia affective flattening avolition/apathy	(1) BRMS depressive symptoms (2) EuroASI problem severity	SHAPS, SANS, BRMS scores did not differ between opioid dependent, alcohol dependent, or multidrug dependent groups EuroASI composites not associated with SHAPS (i.e., anhedonia largely independent from addiction problem severity)
Martinotti, Cloninger, & Janiri, 20081	N = 25 DSM-IV opioid dependence; abstinent at time of study (minimum of 3 months after completion of detox; mean = 10.1 months); recruited from self-help groups	Evaluation of correlations across self-report measures; study included 25 alcohol dependent and 50 healthy controls	(1)SHAPS Consummatory pleasure (2) SANS anhedonia affective flattening avolition/apathy	(1) BRMS depressive symptoms (2) VAS for craving	SHAPS scores ≥ 3 for 12 out of 25 opioid dependent individuals (48%) (i.e., clinically relevant anhedonia) Craving significantly positively correlated with SHAPS scores (i.e., greater anhedonia)
Stevens, Peschk, & Schwarz, 20071	N=25 Males only; Polydrug abusers; DSM-IV opioid dependence; consumed > 0.5 grams heroin intravenously on more than 3 days per week during last 2 months	Single session psychological testing study; included comparison with 26 abstinent polydrug addicts (at least 3 months abstinent), and 26 healthy controls	(1) SHAPS Consummatory pleasure	(1) TAF frequency and intensity of hedonic activities	SHAPS scores differed by group - current heroin users and abstinent polydrug addicts reported greater anhedonia than healthy controls TAF frequency and intensity scores lower for current heroin users compared to healthy controls (i.e., less hedonic activity)
Janiri et al., 20051	N = 24 DSM-IV opioid dependence; abstinent at time of study (at least 45 days since end of detox); recruited from self-help groups, day hospital, or therapeutic community ** Same sample as Pozzi et al., 2008	Psychometric evaluation and comparison of self-report assessments with 22 alcohol dependent and 24 multidrug dependent individuals	(1) SHAPS Consummatory pleasure (2) SANS anhedonia affective flattening avolition/apathy (3) VAS for pleasure hedonic capability	(1) BRMS depressive symptoms (2) VAS for craving (3) SOWS withdrawal	SHAPS, SANS, BRMS, and VAS for pleasure did not differ between opioid dependent, alcohol dependent, or multidrug dependent groups SHAPS positively correlated w/ VAS craving and SOWS; negatively correlated with duration of abstinence SHAPS scores ≥ 3 for 5 out of 24 opioid dependent individuals (21%) (i.e., clinically relevant anhedonia)
Schmidt et al., 20011	N = 16 ICD-10 criteria for opiate dependence; opiate abstinence of 6–36 hours (1st day of detox)	Single session assessment of psychopathology, hormonal testing, and psychomotor performance; study included 17 individuals with alcohol dependence, 10 with major depression, 10 with schizophrenia, and 10 healthy controls	(3) SANS anhedonia affective flattening avolition/apathy (4) Physical anhedonia assessed with “self-rating questionnaire”	(1) Serum growth hormone Dopamine receptor sensitivity (2) Psychomotor reaction time	SANS anhedonia and affective flattening scores higher in opiate dependent subjects compared to healthy controls SANS anhedonia scores were not associated with central dopamine receptor dysfunction or psychomotor performance

1 Study included in Garfield et al 2014 Review

Notes: TEPS - Temporal Experience of Pleasure Scale; CPAS – Chapman Physical Anhedonia Scale; CSAS – Chapman Social Anhedonia Scale; SHAPS – Snaith Hamilton Pleasure Scale; AMSR - Affect-modulated acoustic startle response to emotionally positive, negative, neutral stimuli; fNIRS – functional Near Infrared Spectroscopy; SANS - Scale for Assessment of Negative Symptoms; BRMS - Bech-Rafaelsen Melancholia Scale; EuroASI - European adaptation of Addiction Severity Index; VAS – Visual Analog Scale; TAF - Tubingen Anhedonia Questionnaire; SOWS - Short Opiate Withdrawal Syndrome Scale