Table 1.

Summary of Text Messaging-Based Studies (in order of appearance in review)

Authors	Country (Year)	Sample Size1	Main Eligibility Criteria	Intervention	Control	Concomitant Therapy	Proportion of Primary Efficacy Outcomes Significant2	Proportion of Secondary Efficacy Outcomes Significant2	Detailed Study Results
Haug, Meyer, Schorr, Bauer & John	Germany (2009)	n=194	Daily smokers who text message. Participants were recruited at a university.	Three months of fully-automated texts tailored to stage of change as per the TTM. Texts were customized based on baseline assessments. A craving helpline was also included. Two intervention groups received either 3x/week or 1x/week messages.	Text assessments only	Not discussed	n/a	0% (0/5)	Feasibility and acceptability of this intervention were demonstrated. Measures of efficacy were assessed at 3 months with no directional differences across the 3 groups. Authors indicated that the study was insufficiently powered for these outcomes.
Free, Whittaker, Knight, Abramsky, Rodgers & Roberts	United Kingdom (2009)	n=200*	Smokers ≥ 16 years old, living near London, and willing to make a quit attempt	Same intervention as Rodgers, et al, but tailored to UK smokers	Same as Rodgers, et al	Not described	100% (1/1)	n/a	At 4 weeks, self-reported quit rates (point prevalence) were 26% in the intervention group versus 12% in the control group, RR 2.08 [CI: 1.11, 3.89].
Ybarra, Bagci Bosi, Korchmaros, & Emri	Turkey (2012)	n=151	Daily smokers ≥ 18 years without a chronic or serious illness, in Ankara, and were willing to attempt quitting within 15 days.	Six-week intervention developed based upon review of telephone-based counseling approaches to smoking cessation, emphasized CBT, self-efficacy theory and relapse prevention. Messages were automated and personalized dependent upon an individual’s quitting phase and whether they had relapsed during the intervention. In the pre-quit phase, 5 messages per day were sent, increasing as the quit day approached. Following quit day, messages were gradually tapered to 1 per day.	Information about quitting provided in a 7-page brochure	Pharmaco-therapy allowed for all participants and encouraged in those who smoked ≥ 10 cigarettes per day	n/a	0% (0/5)	The expected total number of messages for participants ranged from 91 to 146, depending upon how their quit attempts fared. Due to technical problems, approximately 20% of intervention participants missed receiving five or more intervention messages, and about 33% received 22 or more duplicate messages. However, data from a 4-week follow-up survey suggest that the intervention was received favorably by participants. Follow-up at 3 months was 40%. Participants did not receive research incentives for participation, since they are not culturally normative in Turkey, and this also may be a causative factor for follow-up rates being lower than in other studies. A number of efficacy outcome measures (sustained and point prevalence) were evaluated at 4 weeks and at 3 months with no significant differences between groups..
Ybarra, Holtrop, Prescott, Rahbar, & Strong	United States (2013)	n=164 (101 in intervention group and 63 in control group)3	Daily smokers (recruited nationally) age 18–25 who were seriously thinking about quitting within the next 30 days.	Six weeks of messages, which were personalized based upon an individual’s quitting phase and whether they had relapsed during the intervention. During the pre-quit phase 4–6 daily messages encouraging them to clarify reasons for quitting and to understand their environmental cues.. On quit day and the day after 9 messages were sent, and were tapered gradually to 4 per day; these messages emphasized negative aspects to quitting and encouraged coping strategies. Afterwards, participants received 2 and later 1 message/week. Messages were automated with the exception of those sent to and from a text buddy.	Texts aimed at improving sleep/exercise habits within the context of how it would help with quitting smoking. Number of texts similar to intervention group.	Pharmaco-therapy encouraged in those who smoked ≥ 10 cigarettes per day	n/a	(67%) 2/3	Results significantly favored the intervention group at 4-weeks: continuous abstinence 39% versus 21%, adjusted OR 3.33 [CI: 1.48, 7.45] and point prevalence 44 % versus 27%, adjusted OR 2.55 [CI: 1.22, 5.30]. Follow-up rates in the intervention and control groups were 86% and 87%, respectively, at 4 weeks and 80% in both groups at 3 months. Self-reported 3-month continuous abstinence (defined as ≤ 5 cigarettes smoked), was, 40% (intervention) versus 30% (control), OR 1.62 [CI: 0.82, 3.21], although the study was not adequately powered for this outcome. At 3-month follow-up, 129/164 (79%) of participants completed a program evaluation designed to assess acceptability of the text messaging system. Eighty-two percent of intervention participants and 74% of control participants said they would be likely to recommend the program to others. Fifty-one percent of participants texted their text buddy at least once during the course of the study; those who felt their quit buddy was supportive and helpful were significantly more likely to have quit at 3 months.
Rodgers, Corbett, Bramley, Riddell, Wills, Lin & Jones	New Zealand (2005)	n=1705*	Smokers in New Zealand ≥ 16 years old and willing to make a quit attempt	Personalized text messages (5 per day until 4 weeks post quit day, and afterwards reduced to 3 per week) until 6-month follow-up. Content was smoking cessation advice, support & distraction. Participants could “pull” text messages when they were craving. Maori (an indigenous population of New Zealand with a particularly high prevalence of cigarette smoking) participants also received Maori-specific text messages. Participants were asked to set a quit date within 30 days of randomization. Messages were fully automated except those sent to and from a “quit buddy,” another participant with similar characteristics and quit days.	1 text every 2 weeks thanking participants for their participation and providing study-related details	Information given about concomitant therapies available from the government	100% (1/1)	60% (3/5)	Twenty-eight percent of participants in the intervention group reported not smoking in the past 7 days at 6 weeks post randomization, versus 13% in the control group, RR 2.20 [CI: 1.79, 2.70]. Sensitivity analyses included biochemical verification of abstinence in a random subsample of participants. Over-reporting of quit rates was discovered; however, it appeared to occur at approximately the same rate in both the intervention and control groups. Thus, results were similar to those in the primary analysis. At 12 weeks, results remained significant (29% versus 19%), RR 1.55 [CI: 1.30, 1.84], but not at 26 weeks (25% versus 24%), RR 1.07 [CI: 0.91, 1.26], which may be a result of differential loss to follow-up (33% in the intervention group vs. 22% in the control group) that occurred because an incentive was offered only to the control group due to resource limitations. It may have also been negatively affected by an over-reporting of quit status in the control group, possibly because some participants thought that their incentive was dependent on their quit status. Continuous abstinence rates were low in both groups; however, the intervention group had a significantly higher number of participants at 24 weeks with continuous abstinence (8% versus 5%), defined as ≤ 3 lapses with ≤ 2 cigarettes per lapse, RR 1.64 [CI: 1.12, 2.42]. For complete continuous abstinence, the data favored the intervention group but was not statistically significant (5% versus 3%), RR 1.50 [CI: 0.92, 2.44].
Free, Knight, Robertson, Whittaker, Edwards, Zhou, Rodgers, Cairns, Kenward & Roberts	United Kingdom (2011)	n=5800*	Smokers in the UK ≥ 16 years old and willing to make a quit attempt	Same intervention as Rodgers, et al, but tailored to UK smokers. Participants were asked to set a quit date within 2 weeks of randomization.	Same as Rodgers, et al	Smoking cessation helpline numbers provided and NRT encouraged	100% (1/1)	100% (3/3)	Continuous abstinence [≤ 5 cigarettes in the past week at 4 weeks follow-up and ≤ 5 cigarettes since the start of the abstinence period at 6 months follow-up (biochemically verified)] rates were 10.7% in the intervention group and 4.9% in the control group, RR 2.20 [CI: 1.80, 2.68]. Multiple imputation was used for missing data. Sensitivity analyses were performed, one in which participants who were lost to follow up were treated as smokers; results remained similar to the main analysis.
Borland, Balmford & Benda	Australia (2013)	n= 3530 *	Current Smokers and recent quitters (within the last 2 weeks) ≥ 18 years who agreed to join a trial about understanding smoking cessation. Participants were either information seekers (primarily callers to a quitline) or were cold contacted from a marketing research database.	Four active groups: 1) text messages only, 2) a CBT-based, tailored internet –delivered advice program only, 3) both interventions together, or 4) a choice of the 3 prior interventions. Texts were CBT-based and provided strategic advice and motivational messages, which were personalized based upon stage of quitting. Participants could also request messages. Messaging frequency varied based upon quit attempts and reported crises.	Brief information on internet and phone-based cessation services.	Pharmacologic aids encouraged, and other forms of help allowed.	0% (0/3)	33% (3/9)	Use of the assigned interventions was only 43%. At 6-months, self-reported sustained abstinence results for all 3 groups that included text messaging versus control were similar, approximate OR 1.5 [CI: 0.9, 2.3].: The odds of abstinence at 7 months (point prevalence) for the text message only group versus controls was 1.26 [CI: 0.94, 1.68] and for the combined and choice groups versus controls were 1.07 [CI: 0.79, 1.42] and 1.11 [CI: 0.83, 1.49], respectively. The overall follow-up rate was 87% and was similar between groups.
Naughton, Prevost, Gilbert & Sutton	United Kingdom (2012)	n=207	Pregnant smokers ≥ 16 years who smoked ≥ 7 cigarettes per week. Recruitment was at midwife visits.	Tailored self-help brochure and text messages, starting at 2 per day and tapering to 0, for 11 weeks. The intervention drew upon Social Cognitive Theory, the Perspectives on Change Model and the Elaboration Likelihood Model. Message content included pregnancy-related risk, coping strategies, outcome expectancy, support, money-saving feedback, quit preparation advice, and smoking status. Participants could request texts.	Non-tailored self-help brochure plus text assessments (but no intervention texts)	Not discussed	n/a	13% (1/8)	The intervention was determined to be feasible and acceptable. While 24% of participants in the intervention group found the texts annoying, and 26% felt they had received too many, only 9% of these participants requested that the text messages be stopped (and they discontinued mostly for other reasons). Most outcomes related to cognitive determinants (i.e., self-efficacy, harm beliefs, and motivation) significantly favored the intervention group. Of the smoking efficacy outcomes examined, only setting a quit date was significant (in favor of the intervention group); however, the study was not powered to detect differences in these measures. Follow-up rates were 88% overall, with no differences between groups.
Brendryen & Kraft	Norway (2008)	n=396*	Smokers (recruited from Norwegian newspaper ads) ≥ 16 years old, willing to make a quit attempt, smoke ≥ 10 cigarettes per day	A 12-month fully-automated digital intervention using the internet, email, phone calls, and texts. Ann interactive voice response-based craving helpline and relapse prevention system was included. Principles from self-regulatory theory, social cognitive theory, CBT, motivational interviewing, and relapse prevention were applied (Brendryen, Kraft & Schaalma 2010; Bramley et al. 2005). Texts were sent 2x per day during weeks 1–2, 3x per day during weeks 3–6, 1–3x per day during weeks 7–8 and 1x per day during weeks 9–54	Self-help brochure	Free optional NRT	100% (1/1)	100% (4/4)	Repeated point abstinence rates (defined as no smoking in the past 7 days at 1, 3, 6 and 12 months, based on self-report for the previous week) were 22.3% in the intervention group versus 13.1% in the control group, OR 1.91 [CI: 1.12–3.26]. Twelve-month abstinence rates (point prevalence) also significantly favored the intervention group, 37.6% versus 24.1%, OR 1.89 [CI: 1.23–2.92]. Follow-up at 12 months was 86% and similar between groups. NRT use was 93% in the intervention group versus 87% in the control group (p=.07).
Brendryen, Drozd & Kraft	Norway (2008)	n=290*	Smokers (recruited from Norwegian newspaper ads) ≥ 16 years old, willing to make a quit attempt, smoke ≥ 5 cigarettes per day	Same intervention as for Brendryen & Kraft	Self-help brochure	Allowed except for NRT (although 24% of participants in the intervention group and 10% of controls reported NRT use)	100% (1/1)	75% (3/4)	Repeated point abstinence rates (defined as no smoking in the past 7 days at 1, 3, 6 and 12 months, based on self-report for the previous week) were 20% in the intervention group and 7% in the control group, OR = 3.43 [CI: 1.60–7.34]. Twelve-month abstinence rates (point prevalence) suggested benefit of the intervention but results were not statistically significant: 33% versus 23%, OR 1.66 [CI: 0.99–2.79]. Twelve-month follow-up was 82% in the intervention group versus 74% in controls.
Whittaker, Dorey, Bramley, Bullen, Denny, Elley, Maddison, McRobbie, Parag, Rodgers & Salmon	New Zealand (2011)	n=226	Daily smokers ≥ 16 years old and ready to quit. Recruitment was targeted at young adults (age 16–25), particularly young Maori.	Six months of video messages from participant-selected role models, who were ex-smokers. Participants also received text messages for 1 week before and on quit day (1/day) and for 4 weeks after (3/day). Afterwards, they received text messages and videos), 1 every other day for 2 weeks and then 1 every 4 days for about 20 weeks. Messages used evidence-based behavior change techniques. Subjects could text “crave” or “relapse” to initiate additional messages.	One video-based general health message every 2 weeks and reminders about the study for 6 months. Control group also set a quit date.	Not discussed in detail, but pharmacologic aids allowed	n/a	0% (0/3)	Only 17% of target enrollment (1300) was achieved. Results of the primary outcome, self-reported continuous abstinence (≤ 5 cigarettes smoked) over 6 months were similar, 26.4% in the intervention group versus 27.6% in controls (p=0.8). No significant differences were found on any of the other abstinence endpoints assessed at other time points. Most participants in the intervention group liked the video messages and the number and timing of video and text messages.
Agyapong, Ahern, McLoughlin & Farren	Ireland (2012)	n=54*	Adults ≥ 18 years with both Major Depressive Disorder & Alcohol Dependence/Alcohol Abuse per the Structured Clinical Interview for DSM-IV	Three months of fully-automated text messages (twice per day) aimed at stress reduction, maintenance of good mental wellbeing, promotion of alcohol abstinence, craving management, promotion of medication adherence and general support.	1 text every 2 weeks thanking participants for study participation	All consenting participants underwent baseline assessments during the third week of a four week inpatient program. They were not precluded from joining any follow-up program.	0% (0/1)	17% (1/6)	Total days of abstinence over 3 months favored the intervention group but was not statistically significant: 88.3 (SD: 6.2) days versus 79.3 (24.1) days, p=.08. Mean reduction in BDI over 3 months was significantly greater in the intervention group (31.58 (SD: 7.7) to 8.6 (SD: 7.9)) versus controls (31.99 (SD: 9.5) to 16.6 (SD: 9.8)), p=.003. Two secondary alcohol-related 3-month endpoints, the Alcohol Abstinence Self Efficacy Scale (AASES) and units of alcohol per drinking day, also favored the texting group, albeit results were not statistically significant: AASES increased from 38.9 (SD:13.8) to 79.5 (SD: 15.9) in the intervention group versus 43.9 (SD: 9.8) to 72.3 (SD: 14.7) in controls, p=.09; units of alcohol per drinking day decreased from 25.0 (SD: 12.4) to 1.13 (SD: 2.94) in the intervention group versus 20.7 (SD: 10.8) to 6.9 (SD: 16.6) in controls, p=.10. The results from three additional alcohol-related endpoints were not statistically significant. The overall follow-up rate exceeded 92% and was similar between groups.
Agyapong, Milnes, McLoughlin & Farren	Ireland (2013)	n=26	Participants in the intervention group of the Agyapong (2012) RCT	Same as above	n/a	n/a	n/a	n/a
Suffoletto, Calloway, Kristan, Kraemer & Clark	United States (2012)	n=45	Adults 18–24 years, presenting at one of 3 Emergency Departments, and identified as hazardous drinkers on the Alcohol Use Disorders Identification Test	Twelve weeks of fully-automated text messages sent as a once weekly sequence of text messages. The intervention was personalized based upon whether participants were abstinent or moderate or hazardous drinkers. Messages described safe-drinking guidelines, assessed participants’ willingness to set a goal to reduce drinking and provided strategies for reducing drinking or exercises to help decisional balance	2 control groups: 1) weekly text message assessments only or 2) one text message per week reminding participants to complete a final survey	Not discussed	n/a	33% (2/6)	Feasibility was demonstrated. Participants found the intervention useful for reducing their heavy drinking (median 5 on a 7-point Likert scale) and would recommend the program to someone who drinks too much alcohol (median 6/7). Overall follow-up rate was 87%, including 93% in the intervention group, 80% in the assessments group and 87% in the control group. At 3 months, 2/6 exploratory efficacy outcomes significantly favored the intervention versus assessments only group, i.e., change in number of heavy drinking days in the last month and change in drinks per drinking day in the last month.
Irvine, Falconer, Jones, Ricketts, Williams & Crombie	Scotland (2012)	n=34 (only intervention group assessed)	Men 25–44 who had regular episodes of heavy drinking and lived in areas of high social deprivation	Thirty six computer-automated SMS and MMS messages sent over 28 days and that incorporated behavior change techniques based on social cognition models and motivational interviewing. Messages were organized by the stages of the TTM and focused on harm reduction, identifying reasons for drinking, and intentions about future drinking. Some messages requested a response.	n/a	Not discussed	n/a	n/a	Feasibility was demonstrated. Ninety five percent of messages sent during the study were delivered. Eighty eight percent of participants responded via text to ≥ 1 of 9 alcohol-related questions and 53% answered ≥ 7 of these questions. Most narrative responses were lengthy and demonstrated engagement with the intervention.
Gustafson, McTavish, Chih, Atwood, Johnson, Boyle, Levy, Driscoll, Chisholm, Dillenburg, Isham, & Shah	United States (2014)	n=349*	Adults ≥ 18 years with alcohol dependence & who were leaving 1 of 5 residential treatment sites	Eight months of TAU plus a smartphone application and text messaging based on self-determination theory. The text messaging component of the intervention included motivational quotes; messages about recovery experiences, reasons for quitting, and the ability to communicate with a counselor. Counselors received electronic notice of elevated participant scores on an abbreviated weekly Brief Addiction Monitor (BAM) for follow-up.	TAU, which varied across sites	Other continuing care encouraged	(100%) 1/1	(50%) 1/2	Number of risky drinking days (self reported via phone call in the previous 30, significantly favored the intervention group overall (mean (SE)): (2.75 (0.34) versus 1.39 (0.34) days, p=.003) and at 4 months ( 3.01 (0.48) versus 1.50 (0.47) days, p=.02) and 12 months (2.60 (0.49 versus 1.13 (0.50) days, p=.03), but not at 8 months (2.65 (0.48) versus 1.54 (0.49) days, p=.10). The odds of self-reported abstinence in the prior 30 days was significantly greater overall in the intervention arm, OR: 1.65 (CI: 1.05, 2.57), increasing from 1.48 (CI: 0.90, 2.43) to 1.7 (1.05, 2.96) to 1.94 (1.14, 3.31) over the same time points. The proportion of participants reporting negative consequences of drinking at any time point did not vary between groups. Overall follow-up rates at 4, 8 and 12 months were 88%, 85% and 78%, respectively.. Based on informal feedback, the time counselors spent responding to participants in the study was considered minimal.
Reback, Grant, Fletcher, Branson, Shoptaw, Bowers, Charania & Mansergh	United States (2012)	n=52*	Out-of-treatment, methamphetamine-using MSMs age 18–65 years	Two-week intervention with 400 pre-written as well as extemporaneous text messages sent by study staff. Messages were based upon behavioral change theories of Social Support Theory, Health Belief Model, and Social Cognitive Theory. Texts were personalized based upon level of MA use, and responses to study text messages.	n/a	n/a	100% (5/5)	n/a	All primary outcomes pertaining to methamphetamine use were significantly improved at 2-month follow-up, including frequency of MA use, length of time since last used MA, whether injected MA in the previous 2 months, whether stopped having unprotected sex on MA and whether stopped using MA. Additionally, significant reductions were seen in 8 out of 10 outcomes pertaining to high HIV-risk sexual behavior with non-primary partners.
Laursen	Denmark (2010)	n=12	Cannabis users subscribed to one of two text messaging packages, Hashfacts or Restart	Automated texts providing facts about cannabis use (Hashfacts) or oriented toward reduction of use (Restart). Hashfacts messages were sent 2x/day for 3 weeks. Restart messages were divided into four phases with different goals related to reducing use and were sent daily for 10 days and then 2–3 per day for 26 days.	n/a	n/a	n/a	n/a	Text messaging recipients who participated in qualitative interviews strongly preferred facts about cannabis (Hashfacts) to messages oriented toward reducing use (Restart). Hashfacts messages were praised for providing new information and for being simple, direct and easy to understand. Restart messages were criticized for being abstract, soft, and pedagogical.

¹An asterisk was placed after the sample size for each study in which the primary outcome measure was adequately or nearly adequately powered. The aggregated findings of adequately or nearly adequately powered smoking cessation studies can be found in the discussion section of the main text.

²Efficacy outcomes include direct behavioral outcomes (e.g., point prevalence of abstinence and number of quit attempts) and do not include other study outcomes, such as cognitive determinants (e.g., self efficacy) or use of NRT.

³An additional 47 randomized participants did not complete an initial online baseline survey in order to begin receiving texts. The software program did not retain their randomization assignment; thus, they could not be included in the ITT analyses.