title: Advancing the understanding of craving during smoking cessation attempts: a demonstration of the time-varying effect model.
abstract: BACKGROUND
  Advancing the understanding of smoking cessation requires a complex and nuanced understanding of behavior change. To this end, ecological momentary assessments (EMA) are now being collected extensively. The time-varying effect model (TVEM) is a statistical technique ideally suited to model processes that unfold as behavior and nicotine dependence change. Coefficients are expressed dynamically over time and are represented as smooth functions of time.
  
  
  METHODS
  The TVEM approach is demonstrated using data from a smoking-cessation trial. Time-varying effects of baseline nicotine dependence (a time-invariant covariate) and negative affect (a time-varying covariate) on urge to smoke during a quit attempt were estimated for monotherapy, combination therapy, and placebo groups. SAS syntax for conducting TVEM is provided so that readers can adapt it for their research.
  
  
  RESULTS
  During the first 2 days after quitting, the association between negative affect and craving was significantly stronger among individuals in the placebo group, suggesting an early positive impact of treatment. For the monotherapy and combination therapy groups, during the second week of the quit attempt, baseline dependence was less strongly related to craving compared with the placebo group, indicating a different positive impact of treatments later in the quit attempt.
  
  
  CONCLUSIONS
  The results reveal information about the underlying dynamics that unfold during a quit attempt and how monotherapy and combination therapy impact those processes. This suggests possible mechanisms to target in an intervention and indicates timepoints that hold the greatest promise for effective treatment. TVEM is a straightforward approach to examining time-varying processes embedded in EMA.
authors: Methodology Center, Pennsylvania State University, University Park, PA;
authors: Stephanie T
authors: ST
authors: Lanza
authors: Sara A
authors: SA
authors: Vasilenko
authors: Xiaoyu
authors: X
authors: Liu
authors: Runze
authors: R
authors: Li
authors: Megan E
authors: ME
authors: Piper
mesh_terms: D000339:Affect; D003131:Combined Modality Therapy; D066249:Craving; D005260:Female; D006801:Humans; D008297:Male; D015233:Models, Statistical; D011600:Psychopharmacology / Q000379:methods*; D012907:Smoking / Q000628:therapy; D016540:Smoking Cessation / Q000379:methods / Q000523:psychology*; D013997:Time Factors; D014029:Tobacco Use Disorder / Q000628:therapy; D016896:Treatment Outcome
references: Psychol Methods. 2012 Mar;17(1):61-77
references: 22103434
references: Chronic Illn. 2006 Mar;2(1):51-8
references: 17175682
references: J Abnorm Psychol. 2000 Feb;109(1):74-86
references: 10740938
references: J Consult Clin Psychol. 2012 Feb;80(1):54-65
references: 22103958
references: Am J Psychiatry. 2012 Jul;169(7):735-42
references: 22648373
references: J Pers Soc Psychol. 1988 Jun;54(6):1063-70
references: 3397865
references: Health Psychol. 2012 Mar;31(2):226-34
references: 21942749
references: Int J Eat Disord. 2007 Apr;40(3):271-6
references: 17177212
references: Br Med J. 1976 May 1;1(6017):1058-61
references: 773501
references: Addict Behav. 2009 Apr;34(4):365-73
references: 19097706
references: J Abnorm Psychol. 2012 Nov;121(4):909-21
references: 22642839
references: Clin Psychol Rev. 2006 Mar;26(2):196-215
references: 16352382
references: Psychopharmacology (Berl). 2011 Aug;216(4):569-78
references: 21416234
references: J Abnorm Psychol. 2006 Aug;115(3):454-66
references: 16866586
references: Arch Gen Psychiatry. 2009 Jan;66(1):88-94
references: 19124692
references: Drug Alcohol Depend. 2011 Sep 1;117(2-3):118-25
references: 21324611
references: Psychol Addict Behav. 2007 Jun;21(2):127-37
references: 17563132
references: Br J Addict. 1991 Sep;86(9):1119-27
references: 1932883
references: J Abnorm Psychol. 2008 Feb;117(1):94-105
references: 18266488
references: MMWR Morb Mortal Wkly Rep. 2002 Jul 26;51(29):642-5
references: 12186222
references: J Consult Clin Psychol. 2004 Apr;72(2):139-54
references: 15065950
references: Am J Prev Med. 2011 Mar;40(3):286-94
references: 21335259
references: Drug Alcohol Depend. 2002 Jul 1;67(2):219-23
references: 12095672
references: Exp Clin Psychopharmacol. 1999 Nov;7(4):354-61
references: 10609970
references: Psychol Rev. 1974 Mar;81(2):119-45
references: 4817611
references: MMWR Morb Mortal Wkly Rep. 2004 May 28;53(20):427-31
references: 15163928
references: Clin Ther. 2002 Apr;24(4):540-51
references: 12017399
references: Psychopharmacology (Berl). 2006 Mar;184(3-4):637-44
references: 16261317
references: J Abnorm Psychol. 2011 Aug;120(3):557-71
references: 21443289
references: Prev Sci. 2012 Jun;13(3):288-99
references: 22246429
references: MMWR Morb Mortal Wkly Rep. 2011 Sep 9;60(35):1207-12
references: 21900875
references: Behav Res Ther. 2009 Oct;47(10):897-900
references: 19631931
references: J Consult Clin Psychol. 2006 Apr;74(2):276-85
references: 16649872
references: Ann Behav Med. 2002 Summer;24(3):236-43
references: 12173681