In practice these criteria are rarelymet, as many interventions have failed to produce differential change on theoretical mediators . However, these “failed” investigations of mediating variables can still be informative about common therapeutic processes, because they still identify modifiable characteristics that explain individual differences in substance use treatment outcome . Our research provides examples of both specific and common mediators in veterans treated for substance dependence and MDD. In Study 1 we found that greater 12-step meeting attendance for veterans in TSF mediated their superior within-treatment depression outcomes, while Study 2 found that greater reductions in 12-step meeting attendance and affiliation following treatment mediated poorer post-treatment drinking outcomes in the TSF group. Both of these findings highlight the impact of differential levels of engagement with community, self-help resources that were specifically tied to the TSF condition. Independent of treatment group, levels of self-efficacy and substance use in the social network predicted future alcohol and drug use in the year following treatment, suggesting these variables were common determinants of substance use in both treatment conditions. These studies also highlighted the value of investigating mediating variables with respect to individual differences in distal risk factors, by finding that neurocognitive impairment impacted substance use indirectly through self-efficacy, 12- step affiliation, and depression. We demonstrated that mediation analyses can assist in explaining the positive impact of specific therapeutic processes, by finding that the impact of greater attendance at 12-step meetings on future drinking were explained by lower levels of depressive symptoms. Altogether these studies provided new information with respect to explaining how treatment processes or individual characteristics relate to differences in substance use outcomes, cannabis grow facility highlighting the value of examining mediating processes in persons receiving treatment for substance dependence and MDD.

In the presence of moderation , the magnitude of association between two variables depends on the level of a third variable . While studies of mediators typically ask how or why, studies of moderators are perhaps best suited to determine for whom or under what conditions treatments are most effective. Treatment related studies of moderators typically examine if a preexisting characteristic influences effects of treatment on substance use outcomes. In previous examples of moderation, TSF was the most effective therapy for patients with social networks supportive of drinking , and CBT was more effective for cocaine users with greater severity at intake . In tune with the shift towards examining therapeutic process variables, there is perhaps greater current interest in identifying moderators that influence relations between process variables and substance use . Statistical recommendations for testing moderated mediation, or “conditional mediation” are now available , with clinical examples published in recent literature . These studies help illustrate heterogeneous pathways to recovery, because the magnitude of benefits conferred by a proximal variable may depend on some other distal risk factors. Because certain distal characteristics are prevalent and relatively intractable in substance-dependent patients, it is critical to explore these complex relationships in the context of addictions treatment. Investigations of such moderators provided further information about the complex associations between therapeutic process variables and treatment outcome for individuals with substance dependence and MDD. While social network characteristics were predictive of future substance use in the sample at-large, moderation analyses revealed these effects were attenuated for certain individuals. More specifically, the predictive effects of social network variables were reduced for veterans who resided in controlled contexts for longer periods of time. Neurocognitive impairment was also found to moderate process variable effects, as veterans with greater impairment experienced relatively stronger benefits from 12-step affiliation, especially when they were severely depressed.

These findings are significant as they reveal the benefits or risks conferred by certain processes are not similar across all recipients of treatment, and that certain contextual factors or individual characteristics impact the relations between these processes and substance use outcomes. The major goal in process-oriented research is frequently to discover factors that explain group differences, especially with respect to differences between treatment conditions. Whether group differences are consistent or inconsistent with hypotheses, studies of mediating variables can provide useful and potentially explanatory information, and our studies provide several examples of this type of contribution. In perhaps the most surprising finding of our controlled trial, the TSF group had superior reductions in depression during treatment, as compared to ICBT which targeted both depressive symptoms and substance use . While reductions in depression during follow-up were greater for ICBT, it was still perplexing that the “addiction-focused” treatment performed better than an intervention designed to target depression. Results of Study 1 provided some insight, suggesting that greater reductions in depression for TSF were likely attributable to greater attendance at community 12-step meetings. In fact, when controlling for meeting attendance, TSF and ICBT were similar on depression. In another unexpected finding, patients with poorer neurocognitive functioning had better substance use outcomes if assigned to ICBT . Patients with poorer cognitive functioning were expected to do worse in ICBT, because CBT is theoretically more cognitively-demanding. A key finding of Study 4 here was that patients with greater neurocognitive impairment had lower 12- step affiliation, suggesting that the poorer outcomes in TSF were likely attributable to difficulties engaging in TSF’s principal therapeutic targets: attendance at 12-step meetings and engagement with prescribed 12-step behaviors. These studies also illustrate that both dynamic, contextual factors and static, distal factors can moderate the effects of therapeutic process variables on treatment outcomes. In Study 3 we examined “controlled contexts”, environments where patients had restricted access to substances , and found these contexts moderated social network effects.

If more time was controlled, having a greater density of network drinking was less predictive of one’s own drinking. For other populations in which utilization of these controlled contexts is fairly common, studies that ignore these moderating contextual effects might underestimate associations between mediating variables and clinical outcomes. Furthermore, our findings demonstrate that effects of certain contextual variables may depend on other contextual factors in predicting substance use or other maladaptive behaviors. In Study 4 the effects of 12-step affiliation on future drinking were moderated by neurocognitive impairment, with stronger effects for the neurocognitively impaired. This interaction was further modified by depression: among patients with greater impairment, having more severe depressive symptoms increased the influence of 12-step affiliation on future drinking. This finding, in particular, reinforces the value of examining proximal variables in conjunction with distal risks and other dynamic processes in the prediction of complex behaviors such as substance use . Study 4, in particular, illustrates there are specific times for particular patients at which certain self regulatory behaviors are especially powerful, and elucidating these complex relationships is an important goal for future clinical research in addictions and other conditions. The strengths of repeated, frequent measurement of variables and specification of appropriate longitudinal models were also illustrated by this series of studies. Establishment of temporal precedence is one of many criteria for identifying a mechanism of change . In our studies time-varying predictors were used in a lagged fashion, with prior levels of process variables predicting future substance use outcomes. While these tests are not sufficient for indication of causation,cannabis grow system establishing temporal precedence increases confidence that adjusting/altering the predictor will result in changes in the outcome variable . Compared to correlational tests, our methods provided stronger evidence that changing 12-step affiliation, negative affect, self-efficacy, and social network variables could alter substance use in patients with substance dependence and MDD. This is an important distinction that strengthens the rationale to target these specific processes in therapy or to design treatments around these goals. Furthermore, we were able to estimate individual patterns of change in process variables and examine associations with changes in outcomes. Many psychological constructs change over time, and this is typically the goal of psychological treatments: to change an adverse condition. However, process variables and outcomes are often studied without consideration of change over time, which can produce biased or distorted results . By modeling within individual change in Study 2, we have stronger support to conclude that within-individual change in 12-step involvement is an important determinant of changes in post-treatment drinking. Adults with substance dependence and MDD historically have poor outcomes from substance use treatment, and are responsible for disproportionate levels of treatment costs and disability. Because these individuals are so commonly represented in SUD treatment settings but have rarely been the focus of treatment outcome or process research, we considered it paramount to explore clinically relevant determinants of substance use within this population. Our sample, in particular, was characterized by low levels of occupational and social functioning, with low rates of employment and marriage. The average participant in our sample had multiple prior inpatient treatments for substance dependence and multiple inpatient episodes for psychiatric problems, highlighting the debilitating and refractory nature of these co occurring conditions. However, it was encouraging to find that, in general, the therapeutic processes with empirically-validated benefits in patients without co-occurring disorders also appeared to confer therapeutic benefits in our sample of adults with substance dependence and MDD.

Because the current studies elucidated relationships between a variety of coping-oriented behaviors, contextual processes, and individual characteristics in the prediction of alcohol and drug use, the clinical implications of these studies are numerous. Several of our findings suggest facilitating 12-step involvement can be a useful component of interventions for patients with substance dependence and MDD. In Study 1 patients in TSF had greater reductions in depression that were mediated by 12-step meeting attendance. Furthermore, greater attendance at 12-step meetings had unique effects on depressive symptoms , which in turn predicted lower future drinking. It has been suggested that patients with co-occurring psychiatric problems may receive amplified benefits from social interaction inherent to self-help meetings, perhaps due to greater severity of social problems and isolation , which may have contributed to improved depression and drinking in our sample. During post-treatment follow-up , maintaining greater 12-step attendance and affiliation over time predicted less increase in drinking, suggesting that continued involvement in 12-step practices can be a beneficial post-treatment maintenance strategy for patients with co-occurring depression. However, one unfavorable finding was that patients in TSF had difficulty sustaining high levels of 12- step meeting attendance and affiliation after conclusion of the formal intervention phase. This suggests that patients with substance dependence and MDD may need some level of ongoing, therapeutic support to continue high levels of 12-step engagement, perhaps through the use of brief motivational/facilitation interventions . These studies were also helpful in elucidating the impact of negative affect in the maintenance of substance use for patients with substance dependence and MDD. We previously found that changes in depressive symptoms and substance use were highly correlated in this sample . The current studies built upon that work by highlighting more specific and unique roles of depressive symptoms. We found that reduced depressive symptoms during treatment were predicted by greater 12-step meeting attendance, independent of current drinking, and mediated the relation between meeting attendance and future drinking. Patients with substance dependence and MDD can likely experience reductions in depressive symptoms by attending 12-step meetings frequently, and these mood changes may help buffer against future drinking. Our findings also suggest that patients who are attending meetings frequently and fail to improve in depression should receive additional intervention or alteration to ongoing treatments to avoid future drinking. Results of Study 4 also indicated that greater depressive symptoms represent a distinct exacerbation of risk for cognitively impaired patients, during which they should engage in greater levels of protective behaviors to reduce the odds of increased drinking. Studies also confirmed significant roles of self-efficacy and social network substance use in the maintenance of abstinence in adults treated for substance dependence and MDD. During post-treatment follow-up, individuals who were generally at higher levels of self-efficacy had lower drinking and drug use. Self-efficacy has predicted good outcomes in a variety of studies and increased significantly during treatment in our sample . Our results only suggest that following the conclusion of formal treatment, patients with low confidence in their ability to abstain from substance use in risky situations are at greater risk for increased frequency of use in the future and may benefit from higher levels of care.