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Affected other interventions: a systematic review and meta‐analysis across addictions

Abstract Background and Aims Individuals impacted by someone else’s alcohol, illicit drug, gambling and gaming problems (affected others) experience extensive harms. To our knowledge, this is the first systematic review and meta‐analysis to determine the effectiveness of psychosocial interventions delivered to affected others across addictions. Methods This review adhered to the Preferred Reporting Items for Systematic Reviews and Meta‐Analyses. An electronic database search (PsycInfo, Medline, Cinahl and EMBASE) of randomized controlled trials (RCTs) published until August 2021 was conducted. RCTs with passive control groups, evaluating psychosocial tertiary interventions delivered to affected others of people with addictions (problematic alcohol use, substance use, gambling or gaming) that did not require the involvement of the addicted person, were included. Results Twenty included studies, published in 22 articles, mainly evaluated interventions for alcohol use, followed by gambling and illicit drugs, with none investigating gaming interventions. The interventions mainly targeted partners/spouses and focused upon improving affected other outcomes, addicted person outcomes or both. Meta‐analyses revealed beneficial intervention effects over control groups on some affected other (depressive symptomatology [standardized mean difference (SMD) = −0.48, 95% confidence interval (CI) = −0.67, –0.29], life satisfaction (SMD = −0.37, 95% CI = −0.71, −0.03) and coping style (SMD = −1.33, 95% CI = −1.87, –0.79), addicted person [treatment entry, risk ratio (RR) = 0.86, 95% CI = 0.75–0.98] and relationship functioning outcomes (marital discord, SMD = −0.40, 95% CI = −0.61, −0.18) at post‐intervention. No beneficial intervention effects were identified at short‐term follow‐up (4–11 months post‐treatment). The beneficial intervention effects identified at post‐treatment remained when limiting to studies of alcohol use and therapist‐delivered interventions. Conclusions Psychosocial interventions delivered to affected others of people with addictions (problematic alcohol use, substance use, gambling or gaming) may be effective in improving some, but not all, affected other (depression, life satisfaction, coping), addicted person (treatment) and relationship functioning (marital discord) outcomes for affected others across the addictions, but the conclusion remains tentative due to limited studies and methodological limitations.


INTRODUCTION
The 5th edition of the Diagnostic and Statistical Manual of Mental Disorders (DSM-5) classifies substance-based and behavioural addictions, including alcohol use, illicit drug use and gambling disorders, as substance-related and addictive disorders, with gaming disorder identified as a condition for further research [1]. Given the negative consequences for individuals, family and friends and communities, these addictions are of public health concern [2][3][4]. International estimates indicate that a large proportion of the population have experienced at least one harm due to someone else's drinking (13-78%), illicit drug use (13-28%) or gambling problem (2-19% [5-8]). The harms experienced by family members and friends (affected others) include emotional or psychological distress, relationship disruption, conflict or breakdown, physical harm and decrements to health, financial harm, criminal activity and reduced performance at work or study [8][9][10][11][12], with recent findings suggesting that the burden of harm contributed by these addictions is comparable [13,14].
Despite these harms, there are limited intervention options for affected others. Available interventions are mainly psychosocial in nature, but vary substantially in their aims. These interventions tend to fall into the following categories: (1) interventions that aim to improve the relationship between the affected other and the addicted person by working conjointly with them (i.e. family systems interventions, such as couples therapy); (2) interventions that are directed towards the addicted person but include the involvement and support of the affected other in the treatment of the addicted person (i.e. family-involved interventions); and (3) interventions that are delivered to the affected other and do not require the involvement of the addicted person (i.e. affected otherdelivered interventions). The aims of affected other-delivered interventions can be twofold, as they can aim to equip the affected other to support the addicted person into treatment or to reduce their addictive behaviour (i.e. affected other-delivered interventions with an addicted person focus) and/or help the affected other manage the impacts of the addicted person's behaviour (i.e. affected other-delivered interventions with an affected other focus [15][16][17]).
A recent scoping review highlighted that despite the needs of affected others, most of the interventions evaluated across the addiction literature have focused upon family systems and familyinvolved interventions [18].
These reviews have shown how, over time, interventions involving affected others have moved away from focusing solely upon family systems and family-involved interventions, the focus of which relies upon the involvement of the addicted person, towards a more holistic approach that takes into consideration the needs of affected others in their own right [17]. They have generally shown promising findings for the effectiveness of all types of psychosocial interventions involving affected others across addicted person (e.g. treatment engagement), affected other (e.g. distress) and relationship/family functioning outcomes (e.g. conflict [17,20]). Five of the six reviews, however, provided a qualitative synthesis of the evidence base [17,[20][21][22][23], which can increase the potential for subjectivity in the interpretation of findings [24], and only two [17,18] conducted a risk of bias assessment that allows for an examination of the validity of the evidence base [17,19,25].
In the only available meta-analysis of affected other interventions, Edwards & Steinglass [19] explored the effectiveness of mainly family systems and family-involved interventions, and few affected other-delivered interventions, for alcohol use problems.
While this meta-analysis was limited by its focus upon addicted person outcomes (with no affected other or relationship functioning outcomes assessed despite the intervention aims) and its use of passive controls and active comparisons in the same meta-analyses (which reduces statistical power to identify intervention effects), the findings revealed that these interventions produced better addicted-person outcomes than those that did not involve affected others.
Although the available systematic reviews and meta-analysis suggest promising findings, their methodological shortcomings preclude definitive statements regarding the effectiveness of psychosocial interventions delivered to the affected other that do not require the involvement of the addicted person throughout addictions, and are now outdated in the face of this rapidly emerging area of research. No systematic review has focused solely upon the effectiveness of psychosocial interventions delivered to the affected other (i.e. affected other-delivered interventions with an addicted person or affected other focus). The current systematic review and meta-analysis will therefore be the first to evaluate the effectiveness of affected otherdelivered interventions across the range of relevant outcomes (i.e. addicted person, affected other and relationship/family functioning outcomes). By exploring affected other interventions across numerous addictions (alcohol use, substance use, gambling and gaming), this systematic review and meta-analysis will identify gaps in knowledge and provide the formative work necessary for the development of evidence-based affected other interventions across these addictions, particularly for the newer behavioural addictions (gambling and gaming).
This systematic review and meta-analysis aims to: (1) determine the effectiveness of psychosocial interventions delivered to affected others across addictions and the durability of intervention effects, relative to passive control groups; and (2) explore whether the meta-analytical findings are robust to clinically relevant factors (addiction type, mode of intervention delivery, therapist-delivered intervention modality and intervention approach) and methodological quality via sensitivity analyses.

METHODS
This systematic review adhered to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA [26]) and was registered a priori with the International Prospective Register of Systematic Reviews (PROSPERO) (CRD42020151875). Differences between the PROSPERO protocol and the published review can be found in the Supporting information.

Search strategy
Medline, PsycInfo, CINAHL and EMBASE electronic databases were searched for peer-reviewed literature published up until 21 August 2021, using a combination of keywords and wildcards relating to addiction (e.g. gambl*), affected others (e.g. famil*), interventions (e.g. treat*) and randomized controlled trials (RCTs; e.g. random*). Title and abstract, English language, adult and human limiters were employed. A Google search of the first 10 pages (100 citations) was conducted to identify relevant grey literature, as was a manual search of the reference lists of all included articles. See Supporting information for the complete search strategy.

Eligibility criteria
Studies were included if: (1) they evaluated the effectiveness of a psychosocial intervention delivered to affected others of alcohol use, substance use, gambling or gaming that do not require the involvement of the addicted person, regardless of whether the intervention aimed to improve the affected others wellbeing or improve the addicted person's treatment engagement or behaviour (i.e. affected other-delivered interventions with an affected other and/or addicted person focus); (2) they were RCTs or controlled trials (i.e. best-quality evidence); (3) they included a passive control group (e.g. no intervention, waiting-list control, assessment only, treatment referral or nonspecific treatment component controls [27,28]); (4) the affected other and addicted person were 18 years of age or older; and (5) they assessed any affected other, addicted person or relationship functioning outcome.
Studies were excluded if: (1) a composite addictive disorder and mental health sample (e.g. affected others of problem alcohol use and/or depression) was employed, whereby the data for the addictive disorder sample were not analysed separately; (2) an RCT with an active comparison condition was employed; (3) the affected other was involved in a treatment that was targeted towards the addicted person (i.e. family-involved treatment); (4) the intervention was couples therapy, family therapy, pharmacological, neurobiological, confrontative (i.e. an 'intervention' where affected others confront the individual in the hope of engaging him/her into treatment) or a non-therapeutic group (e.g. 12-Step programmes); (5) the intervention related to prevention of use rather than tertiary intervention; and (6) the article was a qualitative report, review, case study, conference proceeding, abstract, editorial, dissertation, book, book chapter or protocol paper. Four reviewers were independently involved in the identification of included studies, with double screening conducted for one-third of the identified studies. Discrepancies were resolved through group discussion, with a third reviewer acting as arbiter when required.

Data extraction and risk of bias assessment
A standardized, pilot-tested extraction sheet was employed to extract data from the included articles. Data relating to basic study descriptives (e.g. country), interventions (e.g. intervention approach), outcomes (e.g. measures employed) and meta-analytical data [e.g. means and standard deviations (SD)] were extracted.
Risk of bias was assessed using the revised Cochrane risk of bias tool for randomized trials (version 2.0 [29]), which evaluates bias that may arise across five domains: randomization process, deviations from intended treatments, missing outcome data, outcome measurement and reported result selection. Each study is classified as having either a low risk of bias, some concerns or high risk of bias on each domain, with these judgements then used to determine the overall risk of bias.
Overall, a study can be classified as having: (1) a low risk of bias (all domains classified as low-risk); (2) some concerns (at least one domain is classified as having some concerns and no domains are classified high-risk); or (3) a high risk of bias [at least one domain is classified as high-risk or multiple domains (≥ 4) are classified as having some concerns]. Three reviewers were independently involved in the data extraction and risk of bias assessment. Double data extraction was conducted for one-third of the included articles, whereas the risk of bias for all studies was independently assessed by two reviewers. Discrepancies were resolved through group discussion, with a fourth reviewer acting as arbiter when required. Where available, original articles and published protocols were used for the risk of bias assessment.

Meta-analysis
A series of meta-analyses explored the effectiveness of all affected other-delivered psychosocial interventions for affected others across addictions compared to passive control groups, regardless of focus (i.e. affected other-and/or addicted person-focused). A primary outcome was not selected due to the large number of aims of the available interventions. Moreover, given that 20 different outcomes were evaluated across the included studies, final outcomes for this metaanalysis were selected post hoc whereby outcomes reported in at least five of the included RCTs were selected for inclusion. These outcomes included: (1) affected other outcomes (depressive symptomatology, life satisfaction, addiction-related harms, psychological distress, coping styles, anxiety symptomatology); (2) addicted person outcomes (frequency of use, treatment entry); and (3) relationship functioning outcomes (marital/relationship discord). Only studies that provided sufficient data for at least one of these affected other, addicted person or relationship functioning outcomes were included in the metaanalytical component of this review. Data relevant to the metaanalyses included means, standard deviations and sample sizes for continuous variable and events and sample sizes for categorical variables for each intervention and control arm. Where these data were not available, several attempts were made to ascertain the required data from other sources, including other statistics (e.g. t-values, standard errors, 95% confidence intervals) that could be used to calculate the means and/or standard deviations using standard formulas [30], other papers using the same data set and contacting authors directly.
Two author teams were contacted directly for data, with none responding to the review team.
The meta-analyses were conducted in Review Manager [31].
Random-effects models were used, which provide a weighted esti- respectively; [33,34]). Statistical heterogeneity was assessed using the χ 2 and associated P-value, the Tau 2 statistic and the I 2 statistic (0-40% = minor; 30-60% = moderate; 50-90% = substantial; 75-100% = considerable [35]). Given the relatively limited literature, a minimum of two estimates were required to conduct a meta-analysis. The decision rules for the meta-analyses are presented in the Supporting information.

Sensitivity analyses
To examine whether the meta-analytical findings are robust to clinically relevant factors and methodological quality, sensitivity analyses were conducted. This involved repeating the meta-analyses for each outcome while retaining only articles that met certain criteria. Specifically, the sensitivity analyses were sequentially restricted to articles that explored the effectiveness of: (1) psychosocial interventions for affected others of alcohol use (i.e. addiction type); (2) therapistdelivered psychosocial interventions (i.e. mode of intervention delivery); (3) individually delivered psychosocial interventions (i.e. therapist-delivered intervention modality); (4) community reinforcement approach and family training (CRAFT; i.e. intervention approach); and (5) psychosocial intervention in studies that were rated overall as having a low risk of bias. A minimum of five estimates were required to conduct the sensitivity analyses.

Search results
After duplicate removal, 6381 articles were identified for title and abstract screening. Of these, 150 articles remained for full-text assessment. Twenty studies of 22 articles were included in this review, none of which were identified from the grey literature search.
Of these, 15 studies among 17 articles were included in the metaanalysis. See Figure 1 for a PRISMA flow diagram of these search results and Supporting information for the list of studies excluded at the full-text assessment stage. Table 1  and addicted person focus [36]). Three studies (15.0%) evaluated coping skills training (CST), which helps affected others to cope with addiction-related distress (i.e. affected other-delivered intervention with an affected other focus; [37]). Three studies (15.0%) evaluated the pressures to change intervention, which provides partners with appropriate coping responses that empower them and increasingly incentivize the addicted person to change their behaviour or seek help (i.e. affected other-delivered intervention with an addicted person focus [38]). The remaining studies (45.0%; k = 9) evaluated a range of other affected other-delivered interventions with an addicted person and/or affected other focus (e.g. quality of life therapy).

Risk of bias
Overall, half of the included studies were classified as having some concerns (50.0%; k = 10) or high risk of bias (50.0%; k = 10; see Supporting information, Table S1). When broken down by domain, half the studies (50.0%; k = 10) were classified as having some concerns for bias arising from the randomization process, followed by high (30.0%; k = 6) and low (20.0%; k = 4) risk of bias classifications. Most studies were classified as having a high risk of bias (45.0%; k = 9) for bias arising from deviations from the intended intervention, followed by some concerns (30.0%; k = 6) and low risk of bias (25.0%; k = 5) classifications. Most studies were classified as having low risk of bias (75.0%; k = 15) arising from missing outcome data, followed by high risk of bias (15.0%; k = 3) and some concerns (10.0%; k = 2). Half the studies were also classified as having some concerns (50.0%; k = 10) for bias arising from measurement of the outcome, followed by low (30.0%; k = 6) and high (20.0%; k = 4) risk of bias classifications.
Finally, most studies were classified as having some concerns (80.0%; k = 16) for bias arising due to selection of reported results, followed by low risk of bias (20.0%; k = 4).   Partner is inclusive of spouses, as well as registered or de-facto arrangements.

Meta-analysis
See Supporting information, Figures S1-S22 for the forest plots of the meta-analyses and sensitivity analyses.   Table 3 presents the meta-analytical results for the six affected other (depressive symptomatology, psychological distress, anxiety symptomatology), addicted person (frequency of use, treatment entry) and relationship functioning (marital/relationship discord) outcomes that had a sufficient number of studies at a short-term follow-up to conduct meta-analyses. No significant differences were identified on any of these outcomes. Despite four studies assessing outcomes at a medium-term follow-up time-point (12 months [37,[39][40][41]] and 18 months [39]), no meta-analyses could be conducted due to the use of waiting-list control groups, in which participants in the control group had received the intervention at this medium-term follow-up.

Sensitivity analyses
The results of the sensitivity analyses are presented in Table 4. Given limited follow-up data, these sensitivity analyses were only conducted at post-intervention. There were insufficient studies to conduct sensitivity analyses based on therapist-delivered intervention modality, intervention approach and risk of bias. Moreover, publication bias was going to be evaluated using funnel plots, but there was an insufficient number of studies [42] to allow for meaningful presentation.   and gaming disorder) and across different modes of delivery (e.g. selfdirected). As sensitivity analyses could not be conducted on mode of therapist-delivered intervention modality and intervention approach, more research into these clinically relevant factors is also required.

Mode of intervention delivery
The current findings are somewhat consistent with a previous metaanalysis, whereby affected other interventions were found to be more effective than control groups in engaging the addicted person into treatment at any post-intervention time-point [19]. The current findings, however, were inconsistent with that same review, with no beneficial effect of intervention found for frequency of use of the addiction [19].
The differences in findings may be attributed to the inclusion of all addictions in the current meta-analysis, compared to alcohol only in the previous meta-analysis. Moreover, while this meta-analysis focused upon affected other-directed interventions only, Edwards & Steinglass [19] also included family systems interventions in the same meta-analysis.
These findings, however, need to be interpreted with caution the current review could not conduct separate meta-analyses to tease out the effectiveness of interventions focused upon the affected other, the addicted person or both, among the various outcomes. This was further complicated by studies that measured outcomes that were not directly addressed by the intervention that was being delivered (e.g. marital discord). Finally, several studies were excluded from the current review as they employed active comparison groups, which involves identifying the comparative efficacy of interventions. Given