Table 2.

Summary of the main characteristics of the reviewed serious games (N=29).

Study and game name	Substance addressed	Type of intervention	Theoretical basis		Computational techniques	Evaluation protocol	Mechanism for data security and confidentiality	Main reported results
			Theory	Theoretical construct or intervention technique
Cheng et al [31]—Drugs and the Brain	Methamphetamine	Prevention—education on the impact of methamphetamine abuse on the brain	Not specified	Not specified	Virtual reality learning environment	Pilot study (pre- and posttest measurements) with 175 visitors (aged 6 to 82 years) to a museum	Not specified	Improvement of knowledge of basic neuroscience concepts and understanding and attitudes toward the impact of methamphetamine abuse.
Klisch et al [30]—Uncommon Scents	Inhalants (toxic chemicals)	Prevention—education on the biological consequences and risk of inhaling toxic chemicals	Not specified	Constructive learning	Web-based serious game	Pilot study (pre- and posttest measurements) involving 444 middle school students (sixth-, seventh-, and eighth-graders)	Data collected anonymously	Significant gains in science content knowledge were obtained. A shift to more negative attitudes toward inhalants was also observed. The most negative shift was among eighth-grade students. Posttest knowledge gains were the strongest predictor of attitude change across all grade levels.
Klisch et al [29]—Bitter Pill and Fatal Interactions	Prescription drugs	Prevention—education on the risk of prescription drug abuse	Theory of reasoned action	Not specified	Web-based serious game	Pilot study (pre- and posttest measurements) with 179 high school students (11th and 12th grade) divided into 2 groups assigning each group to a different game (Bitter Pill and Fatal Interactions)	Data collected anonymously	In both groups, the attitudes toward prescription drug abuse became significantly more negative. A moderate effect size in the Bitter Pill group and a large effect size in the Fatal Interactions group were found.
Sánchez and Bartel [39]—Arise	Alcohol and drugs	Treatment—education and building of coping skills for relapse prevention	Not specified	Coping skill training	Web-based serious game	Feasibility study (posttest measurements) with 8 treatment providers and a pilot study (posttest measurements) with 9 adolescents in substance abuse treatment	Data collected anonymously	The treatment providers rated the serious game with high likability and usefulness. Adolescents rated the game as easy to use, highly acceptable, and very useful as a substance abuse relapse prevention tool.
Elias-Lambert et al [28]—Choices & Consequences	Not explicitly mentioned; the study only refers to “substance abuse” and relationship violence	Prevention—education on the substance abuse and relationship violence challenges, the possible actions, and the consequences associated with those actions	Not specified	Situated experiential learning	Multiuser, mobile-based serious game	Exploratory proof of concept (posttest measurements; 6 focus groups) with 44 youth school students (aged >14 years)	Not specified	Participants reported enjoyment related to the visual and auditory aspects of the game and the facts provided to give further information about selected actions and their consequences. In terms of engagement, some of the participants reported that the scenarios were realistic and could connect and engage with them. Other feedback indicates game preference as a learning tool over traditional formats.
Jander et al [41]—What happened?	Alcohol	Treatment—promotes behavior change through developing a favorable attitude, experiencing positive social influences, and developing high self-efficacy toward the behavior	The I-Change Model	Social norms, perceived pressure, and self-efficacy	Web-based serious game	Cluster RCTa (pre- and posttest measurements)—34 schools with 2649 adolescents (aged between 15 and 19 years) divided into experimental (1622) and control (1027) groups	Not specified	The serious game was effective in reducing binge drinking in adolescents aged 15 and 16 years when they participated in at least two intervention sessions. Interaction effects were found between excessive drinking and educational level and between weekly consumption and age. Additional analyses revealed that prolonged use of the intervention was associated with stronger effects for binge drinking. However, overall adherence to the intervention was low.
Epstein et al [32]—Bacon Brains	Alcohol and drugs	Prevention—education on the science of addiction and how alcohol and other drugs affect the brain	Not specified	Not specified	Web-based serious game	RCT (pre- and posttest measurements) with 244 students (sixth to eighth grade) aged 11 to 15 years	Not specified	A more significant knowledge gain among the intervention groups was found compared with the control group. The intervention was helpful in teaching students core concepts about the science of addiction, and the knowledge they learned persisted through posttest assessment. Girls acquired knowledge gains in the collaborative and competitive game conditions, whereas boys demonstrated similar gains only in the competitive condition. Students in the experimental conditions reported enjoying playing the games more than students in the control condition.
Hookham et al [26,27]—Shadow	Alcohol (comorbidity with depression)	Treatment—promotion of behavioral and cognitive change related to mood and misuse of alcohol	Not specified	Cognitive behavioral therapy and motivational interviewing	Web-based serious game where the storyline is based on branching of predefined dialogues	Comparative study (posttest measurements, within-subject) between a gamified and nongamified version of a web-based alcohol abuse and depression treatment with 10 university students (aged 18-30 years)	Not specified	No significant differences were found between the gamified and nongamified versions of the web-based treatment in terms of usability, ease of use, perceived usefulness, or engagement.
Hughes et al [36]—CollegeLiVE	Alcohol and drugs	Prevention—presents typical situations to practice social skills, protective behaviors, and self-reflection	Social cognitive theory and interactive performance theory	Not specified	Virtual reality scenario based on a computational framework that facilitates the creation and remote control of avatars for interaction purposes	Quasi-experimental study (pre- and posttest measurements) with 68 university students (45 in the intervention group and 23 in the control group) aged ≥18 years	Not specified	No significant differences were found between the intervention and control groups when questioned about specific protective behaviors. Nevertheless, the participants in the intervention group were significantly more likely to implement protective behaviors such as trying to stop somebody they knew from deciding to drive after drinking and using a designated driver than the participants in the control group.
Gamberini et al [50]—no name provided	Alcohol and drugs	Prevention—education on and awareness of the risks related to the consumption of psychoactive substances for partygoers	Not specified	Not specified	Multiplayer web-based serious game	Two pilot studies (pre- and posttest measurements), one to assess risk awareness and user experience with 227 participants (mean age 24.7, SD 6.78 years) and the other to assess knowledge increase with 81 participants (mean age 23.4, SD 2.02 years)	Data collected anonymously	The results from the first pilot study indicate that the user experience was high. In the second pilot study, significant differences were found in risk assessment and knowledge of substance consumption risks and coping skills between pre- and postgame sessions.
Boendermaker et al [49]—Shots	Alcohol	Treatment—cognitive retraining of selective attention toward alcohol	Not specified	CBM-Ab	Not specified	RCT (pre- and posttest measurements) with 96 heavy-drinking university students (aged 18-28 years). A total of 33 participants were assigned to the gamified version of CBM-A, 30 were assigned to a regular version of CBM-A, and 33 were assigned to a placebo version.	Not specified	There was an overall decline in alcohol attentional bias, but this effect was primarily driven by the regular training condition. Motivation to train decreased equally in all conditions, indicating that the motivational elements in the gamified version could not sufficiently counteract the tiresome nature of the training. Moreover, motivation to change with respect to planning to drink less in the future increased in the regular and placebo training but decreased in the gamified training condition, which may indicate potential detrimental effects of disappointing gamification.
Boyle et al [51]—CampusGANDR	Alcohol	Treatment—modification of behavior by correcting normative perceptions and inducing reductions in alcohol use	Not specified	Personalized normative feedback	Web-based serious game with Facebook log-in credentials to simulate a social game (but no real social connection)	RCT (pre- and posttest measurements and follow-up) with 237 undergraduate students aged between 18 and 24 years. A total of 113 students were assigned to the use of the serious game, and 124 were assigned to the standard intervention (control group).	Not specified	Participants in the serious game condition reported significantly reduced peer drinking norms and alcohol consumption at the 2-week follow-up compared with participants who received the standard intervention. A mediation model demonstrated that this effect was driven by larger reductions in perceived drinking norms among participants assigned to the serious game.
Damasceno et al [37]—no name provided	Drugs	Prevention—education on the damage of drug abuse and submission of the player to moral decisions	Social cognitive theory	Not specified	PC-based serious game	Pilot study (posttest measurements) with 69 school students (mean age 13.7 years)	Not specified	On the basis of the collection and analysis of in-game behaviors (statistics such as the time spent, correct and wrong answers, and response time), the authors present a general picture of the differences in game performance among groups of users. The authors conclude that serious games could be a powerful tool for drug abuse prevention as an instructional mechanism and for the identification of risk behaviors.
Stapinski et al [52]—Pure Rush	Drugs (focused on cannabis, ecstasy, methamphetamine, and hallucinogens)	Prevention—education on the effects associated with each drug and pairing drug-related cues with negative stimuli	Not specified	Not specified	Web-based serious game with a mobile version for Android devices	Feasibility study (posttest measurements) with 25 students aged between 14 and 17 years and an RCT (pre- and posttest measurements) in 9 schools with 281 students aged between 13 and 16 years. A total of 148 students were assigned to game sessions, and 133 were assigned to the control group.	Data collected anonymously	Results from the feasibility study indicate that students enjoyed playing Pure Rush and found the game age-appropriate and the game’s infographics understandable and appealing. Results from the RCT indicate significant knowledge increase from before to after the intervention in both groups (no significant difference between groups). Knowledge gain was greater in the game condition than in the control group but only in female students. Very low intentions to use illicit drugs were observed in both groups. No significant differences were found in lesson engagement and in future intentions to use drugs between the intervention and control groups.
Earle et al [42]—CampusGANDRV2	Alcohol	Treatment—modification of behavior by correcting normative perceptions and inducing reductions in alcohol use	Self-determination theory	Personalized normative feedback	Mobile-based serious game	RCT (pre- and posttest measurements and follow-up) with 276 first-year university students. A total of 93 students were assigned to the game session receiving standard feedback, 90 were assigned to the game plus supplemented feedback on their perceptions and behaviors, and 93 were assigned to a control group.	Not specified	Participants who were assigned to the game with the supplemented feedback reduced their drinking significantly during the 2 months after the intervention in comparison with control participants. Reduction in drinking behavior was stronger among heavy drinkers.
Duncan et al [53]—SmokeSCREEN	Drugs	Prevention—education and presentation of social situations to develop behavioral skills associated with primary prevention of cigarette and marijuana use	Not specified	Not specified	Mobile-based serious game	Pilot study (pre- and posttest measurements) with 25 adolescents aged between 11 and 14 years	Not specified	Improvements in knowledge were found for both cigarette and marijuana between baseline and after playing. No significant changes in perceived social norms toward both substances were reported. The players provided positive feedback about their experience with the serious game.
Metcalf et al [45]—Take Control	Alcohol and cigarette	Treatment—practice of refusal skills and increase in self-efficacy by denying trigger or cue items in a nonthreatening environment	Not specified	Cue exposure therapy, extinction therapy, virtual reality therapy, and cognitive behavioral therapy	PC-based serious game with Kinect	Quasi-experimental wait-list study (pre- and posttest measurements) with 61 participants aged >18 years. A total of 29 participants were assigned to the intervention group, and 32 were assigned to the wait-list control group.	Data collected anonymously	The results reported that substance use decreased or remained for most users, although more for alcohol consumers than for tobacco users. Participants in recovery for alcohol use reported more benefit than those in recovery for tobacco use, with a statistically significant increase in self-efficacy, attitude, and intended behavior. Participants found the game engaging and fun and felt that playing it would support recovery efforts.
Kapitány-Fövény et al [46]—Once Upon a High	Alcohol and drugs	Prevention—education on the epidemiology and risks of substance use, promotion of health-conscious behavior, and decrease in stigma and negative attitudes and increase in willingness to help peers with substance use problems	Not specified	Self-efficacy	Mobile-based app containing 2 serious games	Quasi-experimental study (pre- and posttest measurements) with 386 students aged between 14 and 18 years from 4 different schools. A total of 255 students were assigned to the intervention group (app use), and 131 were assigned to the control (nonapp use) group.	Data collected anonymously	Users in the intervention group showed a greater decrease in energy drink consumption. No relevant differences between the 2 groups were found in knowledge gaining on psychoactive substances and physical exercise frequency. A correlation between the app’s perceived usefulness and a decreasing frequency of past-month alcohol use was found. Results also indicate that a decrease in negative attitudes toward substance users might be a risk factor for increasing past-month alcohol consumption.
Gamberini et al [54]—no name provided	Alcohol and drugs	Prevention—education on the potential risks of psychoactive substance abuse during nightlife events	Not specified	Not specified	Multiplayer web-based serious game	Quasi-experimental comparative study (posttest measurements) with 136 young adults (mean age 23.5 years). A total of 67 participants used the game, and 69 read leaflets with information on the potential risks of psychoactive substance abuse.	Data collected anonymously	The evaluations of the game credibility and effectiveness were positive. No significant difference was found between game and leaflets except for informativeness, on which leaflets performed better than the game.
Abroms et al [48]—Recovery Warrior 2.0	Drugs	Treatment—helping the patients in the development of negative associations with drugs and acquisition of drug refusal skills	Social cognitive theory and reinforcement theory of motivation	Repetition priming	PC-based serious game with Kinect for body motion and voice recognition	RCT (pre- and posttest measurements and follow-up) with 80 participants aged between 15 and 25 years under a drug treatment program. A total of 36 participants were assigned to the use of the game+treatment as usual, and 44 were assigned to the control group (treatment as usual only).	Not specified	Participants in the intervention group mostly agreed that they would use the refusal skills taught by the game and reported attending more outpatient counseling sessions than those in the control group, but the difference was not significant. Cravings declined for both groups from baseline to the 4- and 8-week follow-up, but the differences between groups were not statistically significant. Self-efficacy fluctuated slightly but did not change widely between the intervention and control groups. The game had no effect on drug use at 4 or 8 weeks after discharge, with the exception of a benefit reported at the 4-week follow-up among participants receiving treatment for marijuana addiction.
Carvalho et al [38]—JiB	Alcohol	Prevention—education on the consequences of alcohol abuse promoting empowerment of the individual, traditional cultures, and social responsibility	Not specified	Not specified	Mobile-based serious game	Pilot study (pre- and posttest measurements) with 23 participants aged between 20 and 29 years	Data collected anonymously	The results were analyzed by dividing the participants into habitual and nonhabitual players. The game presented more positive than negative effects on all users. For habitual players, the game did not have a high level of challenge owing to the low difficulty and small learning curve. A higher game tension was found in nonhabitual players versus habitual players.
Willmott et al [47]—Perfect Pour and Dumb Driver	Alcohol	Prevention—education on the physiological effects of varying levels of blood alcohol concentration on driving ability (Dumb Driver) and on the standard alcohol content of 6 types of alcoholic drinks through a multilevel test of pouring accuracy (Perfect Pour)	Theory of reasoned action	Subjective norms and attitudes	Web-based serious game	Pilot study (pre- and posttest measurements) with 303 students aged between 12 and 17 years	Not specified	A positive relationship between average game duration and attitude was found, indicating that the longer the participants played Perfect Pour, the more positive their attitudes became toward binge drinking. On the contrary, a negative relationship between average score and attitudes indicates that the higher the players scored in Perfect Pour, the more negative their attitudes became toward binge drinking. No significant associations were observed among gameplay metrics, attitudes, and subjective norms for Dumb Driver.
Tan et al [55]—Drug Defense	Alcohol	Prevention—education on the consequences of excessive alcohol use	Social cognitive theory and multiple intelligences theory	Not specified	Mobile-based serious game	Pilot test (pre- and posttest measurements) with 69 university students (aged 18 to 21 years)	Not mentioned	Significant differences between pre- and posttest measurements were found, indicating an increase in knowledge of alcohol. Playability was good according to the values obtained in the evaluation of gameplay, story, and mechanics of the game.
Mostajeran et al [40]—no name provided	Alcohol	Treatment—minimize the occurrence of relapse by practicing to avoid alcohol in a simulated supermarket	Self-determination theory	Cue exposure therapy and approach-avoidance training	PC-based serious game with virtual reality using a head-mounted display	Comparative study (posttest measurements, within-subject) with 13 participants (aged 22 to 35 years). All the participants were assigned to a gamified version of the approach-avoidance training and cue exposure therapy and a nongamified version of the approach-avoidance training.	Not mentioned	All the gamified versions received high usability scores. The gamified version of the approach-avoidance training was more cognitively demanding than the nongamified version. The gamified version of the approach-avoidance training was more motivating than the nongamified version. Participants made fewer errors in the gamified version of the approach-avoidance training than in the nongamified version. The users preferred the mini-game of the approach-avoidance training than the mini-game of the cue exposure therapy.
Yap et al [35]—Drug Defense	Alcohol	Prevention—education on the consequences of excessive alcohol use	Social cognitive theory and multiple intelligences theory	Not specified	Mobile-based serious game	RCT (pre- and posttest measurements) with 140 university students (aged 18 to 21 years). A total of 69 were assigned to the use of the mobile-based game, and 71 were assigned to a video intervention (control group).	Encoding of data and password protection	Participants who used the game showed a significant increase in knowledge scores and a decrease in intent to use but not in actual use. Participants in the video intervention reported a significant increase in knowledge and a decrease in both intent and use. Findings also showed a significant difference in alcohol knowledge for both game and video settings, with the game having a larger effect size than the video.
Ozer et al [33]—INSPIRE	Alcohol	Prevention—education on personal efficacy and skills by providing opportunities to practice strategies for reducing risky health behaviors	Social cognitive theory	Self-efficacy and self-regulation	PC-based serious game with interactive narrative experiences	Pilot study (posttest measurements) with 20 adolescents (aged 14 to 19 years)	Not specified	Trace-log data and self-report questionnaires indicate that participants found the game to be engaging, believable, and relevant to their lives. Within the game, participants also successfully used a range of strategies for avoiding alcohol use. The participants accessed fewer in-game objects than anticipated and spent less time examining the associated infographics designed to affect knowledge of the effects of alcohol use.
Hong et al [34]—One Shot	Alcohol	Prevention—education on and practice of drinking refusal self-efficacy	Social cognitive theory and protection motivation theory	Not specified	Web-based serious game	Quasi-experimental study (1-group, pre- and posttest measurements) with 550 young adults (aged 21 to 25 years) at risk of binge drinking	Not specified	Results show improvements from before to after the game in intention to drink less and in 5 of the 7 indicators of drinking refusal self-efficacy. Risky alcohol decisions within the game and game time predicted enjoyment, which, in turn, predicted intention to drink less and drinking refusal self-efficacy. Enjoyment significantly mediated the effects of game time and risky alcohol decisions on intention to drink less and drinking refusal self-efficacy.
Boyle et al [43]—GANDR	Alcohol	Treatment—modification of behavior by correcting normative perceptions and inducing reductions in alcohol use	Self-determination theory	Personalized normative feedback	Web application (multi-platform) serious game	RCT (pretest measurements and follow-up 1 month later) with 223 first-year university alcohol-experienced students (mean age 18.05 years). A total of 74 students were assigned to the gamified-only intervention, 74 were assigned to the gamified social media intervention, and 75 were assigned to the nongamified intervention (control group).	Not specified	Reported results indicate a significantly greater reduction in drinking at follow-up in the gamified social media condition than in the traditional (nongamified) condition. It was unclear whether the gamified-only condition would lead to greater reductions in drinking than the traditional condition. The gamified-only condition did not lead to a significantly greater reduction in drinking at follow-up compared with the nongamified condition. Relative to the nongamified condition, the gamified social media condition led to significantly greater reductions in drinking for those who were lighter drinkers with less exposure to alcohol-related content on social media.
Boyle et al [44]—LezParlay	Alcohol	Treatment—reduction of risks related to alcohol consumption	Self-determination theory	Personalized normative feedback	Web application (multi-platform) serious game	RCT (pretest measurements and follow-up at 2 and 4 months) with 499 LBQc women aged 21 to >40 years with moderate and heavy alcohol consumption. A total of 143 women were assigned to the gamified intervention on alcohol use and stigma coping, 179 were assigned to the gamified intervention on alcohol use only, and 177 were assigned to the control group.	Not specified	Obtained results indicate that participants who received the intervention on alcohol use and both alcohol use and stigma coping had similar reductions in their weekly drinks, peak drinks, and negative consequences relative to those in the control group at the 2-month follow-up. However, at the 4-month follow-up, reductions in alcohol consumption outcomes faded among those who received the alcohol-only intervention, whereas they remained relatively robust among those who received both the alcohol use and coping intervention. Regarding feasibility, the participants reported the competition to be highly acceptable and psychologically beneficial as a whole.

^aRCT: randomized controlled trial.

^bCBM-A: cognitive bias modification of attention.

^cLBQ: lesbian, bisexual, and queer.