Digital Therapies for Substance Use Disorders: Recent Advances and Engagement Strategies

Introduction

Substance use disorders (SUDs) are a significant public health challenge, with high prevalence and low treatment uptake. In the United States, an estimated 17% of adults met SUD criteria in 2023, yet only about 15% received SUD treatment.¹ Globally, this treatment gap is similarly concerning. Barriers such as limited treatment availability, overall cost, time constraints, and stigma have been shown to limit individuals from engaging in traditional in-person care.¹ Digital therapeutics offer a means to overcome traditional treatment barriers and expand access to SUD treatment.¹ These technology-driven interventions deliver therapeutic content via devices and platforms people use daily. For SUD treatment, digital therapeutics include web-based cognitive-behavioral therapy (CBT) programs, telehealth counseling, automated text message support, and smartphone applications (apps).^2,3

App–based interventions are promising given the ubiquity of mobile devices. In 2024, approximately 97% of US adults reported owning a mobile phone, with 85–90% having a smartphone.⁴ Over 80% of individuals in addiction treatment programs have a smartphone, and a majority reported interest in using app-based tools as a part of their recovery plan.⁵ Health apps thus offer the potential for on-demand, scalable SUD care unconstrained by clinic hours or location. The COVID-19 pandemic accelerated interest in digital modalities for SUD treatment. Pandemic-related lockdowns and social distancing forced many outpatient programs, counseling services, and mutual-help meetings (eg, 12-step groups) to curtail in-person contact. In response, providers and patients rapidly turned to telehealth and mobile apps to maintain care continuity.^2,6 During this period, regulatory changes in some countries expanded tele-SUD services (for instance, allowing buprenorphine initiation via telemedicine), and awareness of digital recovery tools grew. The United States Office of National Drug Control Policy noted the potential for telehealth and apps to expand access to SUD treatment, helping to move digital therapeutics from the periphery and closer to the mainstream.⁷ Overall, there is insufficient evidence to support the general efficacy of apps in reducing substance use; however, specific apps that incorporate evidence-based strategies show the most promise. For example, one study, using meta-regression, showed that CBT and contingency management (CM)-based apps demonstrated statistically significant effects compared to control interventions.²

A potential weakness of app-based treatments, which may contribute to their modest efficacy, is poor user engagement. It is estimated that approximately 77% of users stop using an app within 3 days of installation. Fewer than 10% remain active after 30 days.⁸ Even in controlled trials, where participants are typically more motivated and often compensated, adherence to digital interventions tends to decline after the first few weeks. One study of digital interventions for SUD and mental health reported a median of only 5.5 days of actual use across multi-week study periods.⁵ These issues are compounded by the intersectionality of mental illness and SUD—individuals with co-occurring disorders engage less with treatment and have worse outcomes than those with mental illness alone.⁹

Similar engagement issues are encountered in SUD-specific apps. In a real-world implementation trial of an alcohol-intervention app in outpatient clinics, about half of those who initially engaged stopped using the app by 3 months.¹⁰ Reported reasons included lack of time, forgetting, and losing interest. Many participants described the app as helpful but failed to integrate it into their daily routine. Premature discontinuation may have prevented an otherwise effective intervention from demonstrating its benefit.¹⁰

These engagement barriers highlight the importance of understanding not only what digital interventions include but also how they are designed, delivered, and sustained in real-world use. To integrate emerging evidence across these areas, this narrative review builds on prior meta-analytic work from our group and others to examine app-based interventions for SUD treatment.^2,3 A narrative approach is well suited to this goal, as it allows for integrating new empirical findings, conceptual advances, and implementation experiences beyond the scope of systematic reviews.

We begin by comparing app features associated with demonstrated benefits to identify the essential components of effective digital interventions beyond therapeutic content. We then examine user engagement, drawing on evidence from addiction medicine, behavioral science, and adjacent fields such as mental health and mobile gaming. Next, we highlight strategies that may be used to enhance engagement, retain app users, and ultimately improve treatment outcomes in SUD-focused apps. Finally, we consider gaps in knowledge and future directions, including design considerations and research priorities to advance the field of digital SUD therapeutics. The goal of this review is to inform clinicians, researchers, and policymakers about the current capabilities and limitations of app-based digital therapeutics for SUD treatment and to identify actionable opportunities to strengthen their effectiveness, scalability, and long-term impact.

Methods

We reviewed the National Library of Medicine PubMed database utilizing the Medical Subject Headings (MeSH) terms and keyword searches. Examples of key term searches utilized included: addiction or abuse; substance or abuse; alcohol or addiction; opioid or addiction; alcohol or stimulant addiction or cannabis; addiction or stimulant abuse or detoxication; drug metabolic or substance withdrawal and application; computer software and application; mobile. The focus was to review articles published in the last 10 years, in English. We excluded studies that did not focus on mobile phone applications as a treatment option for patients with SUDs. Ultimately, this led to 14 studies deemed appropriate for inclusion.^2,11–23 We then evaluated these review articles for overlapping studies that identified therapeutic treatment strategies with the highest potential for efficacy.

Overlapping and recurring engagement strategies were synthesized and organized into four themes (user experience, gamification, personalization, and social connectivity) and described across phases of app use (onboarding, ongoing engagement, sustained engagement). As a pragmatic behavioral lens to help interpret why certain features may influence engagement, we considered how strategies align with common determinants of behavior described in the Theoretical Domains Framework (TDF) (eg, reinforcement, social influences, environmental context/resources).²⁴

Current Landscape of SUD Digital Therapeutics: Efficacy and Features

Digital interventions promoting recovery from SUDs include stand-alone, direct-to-consumer apps, along with interventions integrated into formal treatment or aftercare. Randomized controlled trials (RCTs) and systematic reviews have shown that some apps demonstrate clear benefits, while others show minimal or adverse effects.^2,3,25 Emerging evidence indicates that certain features are associated with positive outcomes and others are linked to adverse outcomes.² In this section, we review specific examples of app-based intervention strategies that have been featured in recent reviews^2,3,25 to highlight what appeared to be the most beneficial therapeutic strategies to date.

Evidence from Select Trials

A-CHESS (Addiction-Comprehensive Health Enhancement Support System), a recovery support app for people with alcohol use disorder, was one of the first apps to attempt a large RCT to test the app’s efficacy over 1 year. Adults (n=349) discharged from residential treatment were randomized to 12 months of A-CHESS in addition to treatment as usual (TAU), versus only TAU.²⁶ A-CHESS delivered multiple components, including weekly check-in surveys with semi-tailored feedback, on-demand CBT-based coping tools, a “panic button” to alert someone in the participant’s support network, GPS-triggered alerts when near high-risk locations (eg, bars previously frequented), and a peer discussion forum. Participants receiving A-CHESS had significantly fewer risky drinking days and a higher likelihood of sustained abstinence over 12 months compared to controls.²⁶ Rates of continuous abstinence were approximately 52% in the A-CHESS group vs 40% in controls at 12 months.²⁶ Greater engagement was associated with superior outcomes, with participants who used the app at least weekly having more favorable drinking outcomes.¹⁰

In a smaller study looking at the same population, the LBMI-A (Location-Based Monitoring and Intervention for Alcohol) app was evaluated in a pilot RCT. The app provided personalized support through real-time coping suggestions when participants reported high craving, psychoeducation modules, and GPS-based alerts when nearing high-risk locations.²⁷ In a six-week trial (n=28), those assigned to LBMI-A achieved greater reductions in drinks per drinking day and a higher proportion of abstinent days than a control group that received only a pamphlet and web links.²⁷ While preliminary, this indicated that real-time, tailored interventions via an app could acutely reduce drinking.

Evidence from smoking cessation trials also provides valuable insights for SUD digital therapeutics. In a large RCT (n=684), the multi-component smoking cessation app QuitAdvisor+ contained individualized information about quitting options, daily motivational messaging, a quitting diary, and an individualized quitting benefits tracker. It achieved a 1-month self-reported quit rate of 28.5% vs 16.9% in a control group using a simpler “information only” app.²⁸ Similarly, an RCT of the SmokeFree app found that participants assigned to the full-featured version (eg, daily “missions”, progress tracking, community support) had higher short-term abstinence rates than the minimal information-only version.²⁹ These findings suggest that interactive, theory-driven features such as structured quit plans, tailored messages, and reward systems are more effective than static or purely informational content.

In opioid use disorder, the FDA-cleared app reSET-O (based on an earlier version called reSET)³⁰ has shown benefit when used as an adjunct to buprenorphine treatment. The app delivers a 12-week interactive CBT program with CM, prescribed in conjunction with outpatient pharmacotherapy. Participants who received TAU plus the app were more likely to abstain from opioids in weeks 9–12 (the primary endpoint) than those receiving TAU alone (77.3% vs 62.1%, p=0.02, OR=2.08, 95% CI: 1.10–3.95). Furthermore, participants in the app group also had a lower risk of leaving treatment (HR=0.49, 95% CI: 0.26–0.92).³¹

By contrast, several digital interventions without active therapeutic content have failed to demonstrate benefit. In a Swedish RCT among young adults (n=1932), the alcohol self-monitoring app Promillekoll, which allows users to log drinks and view estimated blood alcohol concentration (BAC) without guiding to reduce consumption, was investigated. App users actually increased their drinking frequency, contrary to the researchers’ hypothesis. The authors concluded that simply providing BAC feedback and informational tools without behavioral intervention components may not be adequate.³² Similarly, in a 6-month trial, the smoking cessation app Stop-Tabac, which delivered generic tips and news but no evidence-based therapeutic content, produced no improvement in quit rates compared with TAU (abstinence ~10% in both groups).³³ A pilot RCT of Coach2Quit, which paired a personal carbon monoxide breath sensor with an app to track smoking behavior, also did not significantly increase tobacco cessation rates over TAU.³⁴ Again, the authors speculated that the lack of behavioral feedback or therapeutic guidance based on carbon monoxide monitoring may have contributed to these negative results.

Findings from these trials suggest that several features are standard to effective SUD apps and often absent from ineffective ones (see Table 1). Apps that deliver or reinforce established treatment strategies (CBT, motivational enhancement, relapse prevention planning, CM) tend to yield better outcomes. Personalization keeps users engaged (eg, content feels more relevant), enhancing efficacy by targeting an individual’s unique triggers. Moreover, when apps were used as adjuncts to formal treatment and clinicians monitored and/or encouraged their use, results were generally more positive^26,29 than when apps were used completely independently. Effective apps frequently include progress tracking (eg, days abstinent, money saved, health improvements), which provides positive reinforcement and self-awareness. Apps providing participant feedback and provider alerts on use trajectories (eg, improvements or concerning patterns) were associated with maintaining behavior change. In contrast, simple tracking without feedback (eg, Promillekoll, Coach2Quit) did not result in improved outcomes.^32,34

Table 1 Features with Evidence-Based Positive Clinical Outcomes

Strategies to Improve Engagement with SUD Apps

Engagement with SUD-focused apps is a major challenge and is directly linked to treatment outcomes.² Successful mobile games, such as Candy Crush, and social media platforms, like Facebook, attract millions of users who return daily, often multiple times per day, over extended periods. This high level of engagement relies on established incentive structures to maximize engagement.³⁵ Although their goals differ from those of health-focused interventions, many of the same principles can be ethically applied to improve engagement with digital therapeutics for SUD treatment.^36–39

Several recent review articles have focused on identifying ideal engagement strategies for mental health-related mobile phone applications.^36–39 These articles offer complementary perspectives on engagement strategies that have proven to be more or less effective. These articles identify four critical elements— user experience, gamification, personalization, and socialization—as central to fostering app engagement among patients with SUDs (see Figure 1). User experience encompasses aspects of apps that facilitate integration into a participant’s life, make the app aesthetically pleasing, and provide confidence in the approach the app is taking. Gamification encompasses aspects that engage a participant’s competitive instincts and desire to recognition within a competitive cohort, as well as elements that make using the app feel more game-like. Personalization encompasses aspects of apps that are tailored to a particular participant or are aware of the individual’s context for use. Finally, socialization within the app includes aspects that facilitate human interaction with other patients or health professionals. Each plays a distinct role depending on the duration of app use (see Table 2).

Table 2 Engagement Strategy Effectiveness by Recovery Stage

Figure 1 Conceptual Framework for Digital Engagement in Substance Use Disorder Treatment. Notes: Framework illustrating early, ongoing, and sustained engagement phases in digital substance use disorder treatment. Core components of personalization, gamification, social connectivity, and user experience interact to enhance motivation, adherence, and recovery outcomes.

Early Engagement (0–30 Days)

User Experience

Many factors can influence an individual’s perception of high-quality versus low-quality user experience. However, a well-designed app onboarding process is crucial for fostering a positive initial engagement with patients of all ages and social demographics.^36–39 An ideal onboarding process should guide users through key features, keeping the initial setup brief and minimizing practical barriers to engagement. In-app tutorials or live professionals should orient users as they explore the app. Thoughtful onboarding reduces friction, supports early follow-through, limits initial drop-out, and helps establish positive expectations for continued use.⁴⁰

The onboarding process should include information on privacy and confidentiality from the outset.⁴¹ Clear, accessible privacy options help build trust, increase the likelihood of honest use of the app and help patients remain anonymous, especially in social settings. The app must also provide participants with control over data sharing (eg, allowing them to choose whether to enable location tracking) and provide clear, transparent explanations of how patients’ data are collected and used.³⁷

Gamification

Gamification can be very helpful in fostering initial engagement. Early rewards and reinforcement encourage users to return.⁴² Apps that provide quick reinforcement, such as check-ins or progress bars, help participants build momentum to establish regular use.⁴² Daily incentives and streak tracking also support routine engagement.⁴¹ However, it is essential to strike a balance between challenges. If early challenges are to easy, boredom can occur, and if they are too hard, they can lead to frustration.^43,44 Studies show that competitive approaches against other (perhaps more experienced) users are perceived as more difficult than collaborative experiences where one works with other users toward a common goal.⁴⁵ Beginning with simple tasks and progressing to more complex ones is often a safe approach to build confidence and a sense of progression without frustration.

Personalization

Tailoring app content to each user’s goals and circumstances increases relevance and supports both early and sustained engagement.³⁶ For example, during enrollment, users could identify their primary objectives, such as maintaining sobriety, gradually reducing consumption, or improving their mental health. The app’s dashboard could then prioritize features that align with these goals and intentions. Contextual interventions could further enhance engagement by delivering prompts at high-risk times or locations, such as evenings, weekends, or areas associated with prior substance use.^26,44 Even simple personalization, such as greeting users by name, referencing past achievements, or offering supportive messages after a lapse in engagement, can make the app feel more responsive, empathetic, and non-judgmental.⁴⁶

Social Connectivity

For SUD treatment groups, using peer recovery coaches or licensed counselors adds accountability and empathy that digital tools lack. Similarly, early adoption of mobile phone applications for SUD is significantly enhanced by engagement and interaction with professionals.³⁶ Integrating human support into SUD apps can boost engagement and effectiveness by strengthening accountability and social support. Providers can monitor app data and discuss progress during sessions for users already in treatment, reinforcing accountability.⁴⁷ For those outside of formal care, in-app coaching services, such as text messaging or video calls with peer recovery coaches or counselors, can encourage and provide personalized guidance.^48,49 The addition of human contact can help extend an app from a self-help educational tool to an impactful component of care.⁴⁷ Designating a supportive friend or family member to receive updates or alerts when concerning patterns arise and further strengthen accountability and sustain engagement.

Ongoing Engagement (1–6 Months)

User Experience

Push notifications are helpful user experience design features that promote ongoing engagement. Notifications as a design feature need to be timely, relevant, and user-controlled. Starting with daily prompts can help cue attention and build habits. These can be transitioned to event-based alerts after a period of inactivity or upon the delivery of new content. Messages should be short, friendly, and actionable, like “Tip of the day: When cravings surge, try a two-minute walk. Open the app for a guided exercise”. Regular updates to notification content can maintain its relevance, and providing notifications with substantive information rather than purely promotional messages may support ongoing user engagement.^50,51 However, overuse of notifications can cause fatigue and lead users to mute alerts altogether, removing their benefit.^50,52

Gamification

Incorporating gamified features can also help sustain engagement by recognizing users’ consistency and progress and providing ongoing reinforcement.⁵³ For example, apps may award points or virtual “coins” for completing daily check-ins, activities, or sobriety milestones. These points or “coins” could unlock new app content and features or be exchanged for tangible rewards, such as coupons or gift cards, that mimic clinic-based CM strategies.⁴⁹ Multi-day challenges and unique digital rewards (like badges) also boost engagement through achievement.⁵⁴ Progressive challenges, where users unlock new skills, modules, or feedback as they advance, help sustain curiosity and promote persistence.⁵⁵ The best design invites persistence without overwhelming the user.⁴³ For example, features that encourage users to stay engaged by letting them reset streaks or recover points after a lapse support participation rather than discouraging it.⁵⁶

Personalization

Personalized push notifications also play a crucial role in ongoing engagement and can help prevent fatigue from overuse. Evidence suggests that tailoring message timing and tone enhances adherence to app-based interventions.²⁸ However, qualitative studies indicate that reminders are most effective when users are already motivated and when delivery feels supportive rather than intrusive, reinforcing perceived usefulness.⁵⁰ Context-specific prompts may further enhance engagement. For example, the HeartSteps app, which delivers activity reminders based on location and time, increased step counts by 24% immediately after delivery versus no prompt. However, effects diminished with the growing use of notifications, suggesting users became habituated.⁵¹

Social Connectivity

Social features provide another avenue for sustained use. Many consumer apps maintain engagement by leveraging social dynamics. Because addiction recovery often involves addressing social disconnection, features that facilitate peer interaction, whether through mutual support groups or in-app communities, may be particularly valuable.

Building opportunities for peer interaction within an app can counter isolation and foster accountability through social influence. Features such as moderated forums, group challenges, or anonymous message boards allow users to share experiences and receive support. Scheduled events, such as live group chats or Q&A sessions with content experts, can create reasons to return regularly. Clear community guidelines and active moderation are needed to ensure these spaces remain safe and recovery-oriented.⁴¹ Furthermore, community leaderboards related to the app’s gamification can tap into users’ competitive instincts and create a sense of flow, while collaborative tasks foster shared purpose and connection.⁴⁵

Sustained Engagement (>6 Months)

User Experience

Sustaining user interest requires that apps evolve over time. Adding new educational materials, guided exercises, or seasonal resources can provide users with a reason to stay engaged long term. Incorporating brief announcements (eg, “New today: a guided meditation for stress”) can re-engage lapsed users and help prevent the experience from becoming stagnant.

Sustained engagement strategies focused on user experience should evolve based on user data and feedback. Analytics can identify drop-off points, prompting targeted interventions at those times. Underused features can be refined or removed to streamline the experience. Communicating improvements back to users (for example, “New version: craving forecast added based on your feedback”) reinforces that their input matters and strengthens investment in the app.⁵⁷

Personalization

Over time, an adaptive system should personalize messaging by observing engagement patterns and adjusting the frequency or content accordingly. Apps are more likely to persist when they align with existing routines rather than feel like an added burden.⁵⁸ Some apps synchronize with calendars to schedule brief check-ins at natural times, such as morning planning or evening reflection.³⁷ Integration with wearable devices can provide discreet prompts based on sensor data, such as a smartwatch vibration, prompting a craving intervention.²⁵ Embedding activities into daily habits, such as the daily commute, lunch break, or bedtime, can help engrain the intervention as a consistent aspect of one’s recovery and support self-regulation over time.³⁷

Gamification

Games often use fresh content or limited-time events to keep users engaged, and health apps can adopt similar strategies.⁴² Weekly challenges, rotating educational materials, or minor visual updates can make the experience feel current and relevant. Rotating challenges or updating notifications and prompts signal that the app remains active.

Social Connectivity

Over time, engaged participants may take on roles as community “champions”, welcoming newcomers and modeling positive behavior, which further strengthens commitment and a sense of belonging to the app community. Qualitative studies have shown that SUD app users who participated in peer discussions reported greater accountability to their online peers and higher overall activity.¹⁰ A systematic review of 263 studies found that social gaming enhanced relatedness and social presence, suggesting that collaborative features can strengthen community ties and sustain participation.⁵⁹ Survey data from the COVID-19 pandemic further support these benefits, as social gaming helped individuals maintain contact during a period of widespread isolation.⁶⁰

Future Directions

Mobile apps and other digital tools have emerged as potential supports in SUD treatment and recovery. The increasing comfort with telehealth has aligned with the expanding interest in digital therapeutics overall, yet to realize their full potential, these tools must overcome both efficacy and engagement hurdles.³

A central challenge is the lack of long-term efficacy data. Most existing trials follow participants for only three to six months, leaving unanswered whether digital tools provide benefits one or two years later. It remains unclear whether time-limited use is sufficient or whether periodic re-engagement, like booster sessions in chronic disease management, is needed to sustain gains. Given the continuing risk of relapse, health systems may need to provide ongoing access to recovery apps.

Real-world implementation research is equally important. Evidence from controlled settings does not always translate into practice. Barriers such as clinic workflow, staff familiarity, and technical support can limit use.⁶¹ Dissemination strategies, such as integrating apps into discharge planning, employee assistance programs, or outpatient follow-up, may promote adoption; however, the best approach to implementing this is unknown and requires further study. As digital therapeutics become more established, healthcare payers may begin to reimburse them or include them in benefit plans, thereby encouraging providers to adopt them. Indeed, one prescription digital therapeutic for SUD (reSET) has FDA approval and some insurance coverage, suggesting a pathway for others.³⁰ However, FDA review applies to only a subset of products that meet criteria as Software as a Medical Device (SaMD). Many SUD-related apps fall outside that pathway, so clinical claims, supporting evidence, and privacy practices vary widely and are not consistently subject to FDA premarket review.

Rapid technological progress is likely to expand the capabilities of digital tools in recovery care. The reasons for continued or resumed substance use are multifactorial and complex to isolate, but new analytic methods may help identify patterns that preceded relapse. Artificial intelligence and biosensor technologies can analyze multiple individualized factors to more effectively stratify risk and guide interventions.²⁵ For example, machine learning could detect changes in user engagement or mood reports and prompt supportive feedback, such as, “It looks like you’ve been isolating more and feeling down. These changes sometimes occur before returning to use. Here are some suggestions”. Biosensors could transmit relevant physiological data directly to apps, reducing user burden and allowing earlier detection of concerning trends. Prototype devices already exist, including wearable alcohol sensors and smart pill dispensers that monitor medication adherence.²⁵ Integrating such tools with recovery apps could enhance accountability and provide real-time data; however, these advances raise essential privacy and autonomy considerations.⁴⁴ Transparent communication and user choice, facilitated through an opt-in design, will be crucial. More research is clearly needed to tailor content delivery for specific patient contexts and presentations. For example, an individual ambivalent about change may benefit from motivational enhancement and harm reduction, whereas someone recently discharged from treatment might require relapse-prevention support. Adolescents may prefer a more gamified or peer-network-focused platform, while older adults may prioritize simplicity and clarity. Digital therapeutics can also be combined with medications and counseling as part of an integrated care plan. For example, a patient with opioid use disorder might receive buprenorphine, therapy, and a recovery app simultaneously, each addressing different aspects of treatment.³¹

Clinicians ultimately want effective interventions. For medications, benefit depends on adherence. For digital therapeutics, benefit depends on engagement, making this a critical area of study. Four major engagement themes have emerged from the literature (see Figure 1). Given the complex and sometimes treatment-refractory nature of addiction,⁶² practical approaches will likely require combining multiple tactics rather than relying on a single method. By implementing these strategies, SUD digital interventions can become more engaging and better integrated into daily life. Enhanced engagement leads to more consistent receipt of therapeutic content. This is technically and clinically important, as greater engagement with evidence-based content has been correlated with better clinical outcomes.²

In a new paradigm where digital tools play a significant role in SUD treatment, addressing the digital divide becomes crucial. While many people have smartphones, not everyone has equal access to or comfort with technology, which risks digital therapeutics inadvertently exacerbating existing disparities. Coaching solutions, such as partnerships with libraries or community centers to provide digital access and coaching, may help extend reach to underserved populations. Future efforts could include training and support for people who are less familiar with apps, and in some cases, alternate formats such as text messaging or phone-based support may work better. Long-term sustainability may depend on how digital therapeutics are financed and built into insurance benefits. Coverage could speed adoption by lowering out-of-pocket costs, but it could also widen disparities if reimbursement primarily supports commercial payers. Keeping apps affordable is important, since expensive devices or recurring app access fees could exclude many potential users. Finally, tailoring content through language, cultural values, or spiritual framing can also improve inclusivity and impact.³⁰

This article has several limitations. First, we focused our search on PubMed and the included articles’ bibliographies, which may have led us to miss relevant work indexed elsewhere. Second, digital therapeutics encompass a wide range of software-delivered interventions. This review centers on engagement, drawing primarily from the app-based SUD literature while also incorporating supporting evidence from adjacent contexts where engagement has been studied more extensively. The time-based engagement phases used to organize strategies were intended to serve as practical guideposts rather than fixed stages; some individuals may move through them faster or slower depending on clinical needs and treatment setting. We emphasize smartphone-delivered tools because they are common in real-world rollout and align with how many patients access digital support. This focus may have limited attention to other modalities. Third, because engagement is defined and measured inconsistently across studies, we chose a narrative approach. A systematic review could improve completeness and transparency, but it would still be limited by inconsistent definitions, and reporting is engagement across studies. Finally, because the app marketplace changes quickly, durable engagement principles were the focus rather than drawing conclusions about specific products or platforms.

Conclusion

Digital therapeutics for SUD treatment have advanced rapidly over the past decade. Mobile apps extend care beyond clinics by offering ongoing recovery support wherever it is needed. Because apps are relatively inexpensive, easy to update, and widely accessible, they have real potential to narrow the treatment gap and reach people who might otherwise not receive support. The goal is to strengthen human care by empowering anyone seeking recovery to access evidence-based digital tools that work in harmony with compassionate professionals and supportive peers. Early research has been encouraging; however, the current app’s evidence base leaves several practical questions unanswered. Many studies do not follow patients long enough to know the enduring effects of apps. Engagement is inconsistently assessed, limiting comparisons across apps and making it difficult to define a meaningful “dose” (amount and duration of use). SUDs are also heterogeneous, including meaningful differences within a single substance (eg, stimulant use via inhalation, insufflation, or injection), and future studies should better account for this clinical variation when designing and evaluating interventions. Gamification and related strategies must always be implemented with care. The intent should be to educate and reinforce positive behaviors such as coping, and help-seeking, not to trivialize addiction or create unhealthy dependence.⁶³ When applied thoughtfully, these methods can make recovery more interactive, rewarding, and sustainable.³⁷ Finally, there remains limited evidence on policy and economic impact, including whether apps reduce downstream utilization. Wide-spread implementation and utilization will depend partly on how these tools are financed and incorporated into routine care, and whether reimbursement decisions expand access or unintentionally widen disparities. Future studies should prioritize longer-term outcomes, standardized engagement measurement, and app designs that reflect clinical differences across SUDs. Closing these gaps will help clarify where apps add the most value in SUD treatment.