Is the relapse concept in studies of substance use disorders a 'one size fits all' concept? A systematic review of relapse operationalisations

ISSUES

Relapse is a theoretical construct and empirical object of inquiry. It is unclear how relapse is operationalised with regard to the various phases in substance use disorders (SUD). The aim was to investigate relapse operationalisations in SUDs studies after short- and long-term abstinence and remission, recovery and slip/lapse.

APPROACH

Systematic review using the following databases: Epistemonikos, Cochrane Central Register of Controlled Trials (CENTRAL and DARE), MEDLINE, EMBASE, Google Scholar, CINAHL, Web of Science and PsycINFO. Search returned 3426 articles, with 276 meeting the following inclusion criteria: empirical study published in English in a peer-reviewed journal; samples meet diagnostic criteria for dependence syndrome or moderate-severe drug use disorder or alcohol use disorder; reports relapse, abstinence, recovery, remission, slip or lapse. Review protocol registration: PROSPERO (CRD42020154062).

KEY FINDINGS

Thirty-two percent of the studies had no definition of 'relapse'. Most relapse operationalisations were defined according to measure (26%), time (17%), use (26%) and amount and frequency (27%). Of the 16 studies with a follow-up duration of up to 2 years, one (6%) contained a definition of 'long-term abstinence'. Of the 64 studies with a follow-up duration of more than 2 years, four (6%) contained a definition of 'long-term abstinence'. Of those, one (2%) mentioned 'early relapse' and one (2%) mentioned 'late relapse'.

IMPLICATIONS

Future research is needed to explore the possible difference between early and late relapse. Moreover, working to increase consensus on relapse operationalisations in SUD research is warranted.

CONCLUSIONS

We identified no consensus on relapse operationalisations nor agreement on the differentiation between early and late relapse. The clinical utility of current relapse operationalisations seems low and may compromise knowledge accumulation about relapse and implementation of research into treatment.

Safety and Feasibility of Nucleus Accumbens Surgery for Drug Addiction: A Systematic Review

BACKGROUND

Substance addiction encompasses the incapacity to discontinue urgent drug use; many severely disabled patients might be considered appropriate candidates for surgery due to the high rates of relapse despite conservative treatment. A crucial finding in the brain of these patients is increased extracellular concentrations of dopamine in the nucleus accumbens (NAcc).

OBJECTIVES

To determine the efficacy and safety of NAcc surgery for the treatment of substance dependence.

MATERIALS AND METHODS

Adhering to PRISMA guidelines, we performed a systematic review to identify all original studies in which NAcc surgery was performed to treat relapsing drug addiction with a minimum follow-up of six months. From database inception to April 10, 2020, we searched PubMed, Scopus, and LILACS. Two reviewers independently selected studies and extracted data. The main outcome was the relapse rate. The GRADE methods were applied to evaluate the quality of evidence. This study was registered with PROSPERO CRD42020177054.

RESULTS

Fifteen studies involving 359 participants met inclusion criteria; eight (56%) included NAcc deep brain stimulation (DBS) in 13 patients with addiction for alcohol (N = 6, 46.1%), opioid (N = 4, 30.7%), and nicotine (N = 3, 15.3%); seven studies (N = 346, 44%) performed NAcc radiofrequency (RF) ablation for opioid (N = 334) and alcohol (N = 12) dependence. Relapse rates were 38.4% for DBS and 39% for RF ablation.

CONCLUSIONS

Despite available studies reporting a benefit in the treatment of drug addictions with NAcc surgery, this systematic review stresses the need for carefully planned prospective studies in order to further address the efficacy and indications.