Table 4.
Within-person changes on theorized mechanisms of change from baseline to the end of treatment.
| Construct, scale | Cronbach alpha at baseline | Baselinea, mean (SD) | Scale range | 2-week versus baseline | ||
| bb (CI) | P value | |||||
| Happiness | ||||||
| PANASc (past week positive affect) | .88 | 3.6 (0.6) | 1-5 | −0.2 (−0.4 to 0.1) | .17 | |
| PANAS (past week negative affect) | .83 | 1.7 (0.5) | 1-5 | 0.1 (−0.1 to 0.4) | .27 | |
| Single item—how happy right now | —d | 69.9 (17.8) | 0-100 | −6.0 (−13.9 to 1.9) | .13 | |
| Satisfaction with Life | .81 | 4.0 (1.2) | 1-7 | 0.2 (−0.2 to 0.6) | .36 | |
| Subjective Happiness | .88 | 5.4 (1.3) | 1-7 | −0.1 (−0.5 to 0.3) | .52 | |
| Self-efficacy | ||||||
| SEQ-12e (internal cues) | .92 | 44.9 (24.3) | 0-100 | 16.7 (7.2 to 26.3) | .001f | |
| SEQ-12 (external cues) | .88 | 47.3 (25.3) | 0-100 | 15.8 (5.4 to 26.1) | .004f | |
| Desire | ||||||
| Questionnaire of Smoking Urges (smoking urges) | .86 | 3.1 (1.1) | 1-7 | −0.8 (−1.3 to −0.3) | .002f | |
| Breadth of thought-action repertoire | ||||||
| Twenty Statement Test | — | 9.5 (6.8) | 0-20 | −2.5 (−5.2 to 0.3) | .08 | |
| Processing self-relevant health information | ||||||
| ATSg (adverse effects) | .94 | 4.2 (0.9) | 1-5 | 0.0 (−0.3 to 0.4) | .86 | |
| ATS (psychoactive benefits) | .81 | 3.6 (0.8) | 1-5 | −0.5 (−0.9 to −0.2) | .006f | |
| ATS (pleasure) | .88 | 3.0 (1.0) | 1-5 | −0.4 (−0.7 to −0.0) | .03h | |
| DCBi (importance of pros of smoking) | .64 | 48.6 (21.8) | 0-100 | −11.3 (−18.9 to −3.8) | .004f | |
| DCB (importance of cons of smoking) | .64 | 60.6 (25.6) | 0-100 | −4.3 (−13.8 to 5.2) | .37 | |
| Single item—pros of quitting | — | 92.3 (11.0) | 0-100 | −6.6 (−14.7 to 1.5) | .11 | |
| Single item—cons of quitting | — | 50.4 (39.9) | 0-100 | 2.0 (−16.8 to 20.7) | .83 | |
| Commitment to Quitting Smoking Scale (commitment to quitting) | .91 | 3.8 (0.7) | 1-5 | −0.2 (−0.5 to 0.2) | .35 | |
| Single item—how motivated | — | 88.0 (13.7) | 0-100 | −5.1 (−12.6 to 2.4) | .18 | |
aBaseline occurred before SiS download, and 2-week follow-up occurred at the end of the prescribed 21 days of app use (ie, 2 weeks post quit day).
bRepeated measures mixed effects model parameter estimate.
cPANAS: Positive and Negative Affect Schedule.
dNot applicable.
eSEQ: Self-Efficacy Questionnaire.
fFlags differences with P<.01.
gATS: Attitudes Towards Smoking.
hFlags differences with P<.05.
iDCB: Decisional Balance Inventory for Smoking.