1. Relative Reinforcing Efficacy of Cigarettes among depressed and non-depressed smokers
Sara weidberg, alba González-roz, aris grande-gosende & Roberto secades-villa
Addictive behaviors research group. University of Oviedo, spain.

2. FINANTIAL SUPPORT CONFLICT OF INTEREST
Spanish Ministry of Economy and Compititiveness (MINECO) (BES ).
CONFLICT OF INTEREST
None to declare

3. Cigarette smoking: a behavioral economics perspective
Aim of behavioral economics in smoking research:
to assess how changes in tobacco cost affect cigarette demand.
Cigarette Purchase Task (CPT)
New method for assessing cigarette demand in smokers
Advantages of the CPT:
Time and cost-efficient measure
Avoids ethical issues
Valid measure
Definir CPT: (CPT), which assesses
hypothetical cigarette purchases as a function of escalating
Prices
Valid measureIncremental, predictive and convergent validity

4. The association between smoking and depression
Individuals with depression are twice as likely to be smokers when compared to individuals who are not depressed (Mendelsohn, 2012).
Individuals with severe depressive symptoms smoke at high rates compared to those smokers without depression (Lasser et al., 2000).
About 40% of individuals with Major Depressive Disorder (MDD) smoke (Grant et al., 2004).

5. Limitations of previous research
Very few studies have examined cigarette demand while considering depressive symptomatology (Audrain-McGovern et al., 2014; Dahne et al., 2016).
Sample characteristics from previous studies preclude their findings from being generalized to a clinical population of smokers with depressive symptoms.
INICIO DIAPO: As depressive symptoms are associated with declines in non-smoking alternative reinforcers across time (Audrain-McGovern et al. 2011), it is essential to examine whether this group of smokers is less sensitive to price changes. This might yield important information on tobacco taxation and pricing in this high-risk population.
OBJETIVO GENERAL: This study aimed to fill these gaps in the literature by examining cigarette demand in a clinical sample of smokers with elevated depressive symptoms for the first time
Sample characteristics form previous studies: being male, non-treatment seekers and young smokers
AIM OF THE STUDY:
To explore differences between smokers with no depressive symptomatology vs. elevated depressive symptoms in the individual CPT demand indices. It also sought to assess the predictive capability of depression over demand indices.

6. Elevated depressive symptoms (n =80)
Method
Inclusion criteria:
Being aged ≥ 18
Meeting criteria for nicotine dependence according to the DSM-IV-TR
Having smoked 10 or more cigarettes per day within the last year
*For smokers with depression: scoring ≥20 on the BDI-II (at least moderate depressive symptomatology).
N = 165 treatment-seeking smokers
Elevated depressive symptoms (n =80)
Low depressive
symptoms (n =85)

7. Method Instruments Sociodemographic questionnaire Nicotine dependence
Number of daily cigarettes
Years of regular smoking
Fagerström Test for Nicotine Dependence (FTND)
Smoking biomarkers:
CO Smoking status: ≤ 4 ppm
Cotinine Smoking status: ≤ 80 ng/ml
Depressive symptomatology
Beck Depression Inventory-Second Edition (BDI-II)
Cut-off point ≥20
A 20 cut-off score was used to differentiate between smokers with and without depression

8. Method
Pearson product-moment correlations  examine the association between the individual CPT demand indices and CO and cotinine levels.
Predictive value of depressive symptoms (BDI-II scores) over each CPT index (BDI-II scoresCPT)
Independent models Simple regressions
Covariate models Hierarchical multiple regressions
Covariates (significant variables in the bivariate analyses):
Nicotine dependece: number of daily cigarettes, years of smoking, FTND score, and CO.
Sociodemographic variables: sex and monthly income
Anxiety symptoms

9. Breakpoint (first price at which consumption is suppresed)
Cigarette cost
How many cigarettes?
€.00 (FREE)
 50 €4
10 
€.01 €5 2 
€.02
€10 1 
€.05
€20  0
€.10
€50 0 
€.25
€100
€.50
 35
€250 €1
 30
€500 €2
€1,000 €3
 15
THE CIGARETTE PURCHASE TASK
How many cigarettes would I buy at each price?
Definir índices CPT:
Breakpoint (first price at which consumption is suppresed)
Intensity (cigarette consumption at zero cost)
Elasticity (sensitivity of cigarette consumption to rises in cost)
Omax (maximum cigarette expenditure)
Pmax (price at which expenditure is maximized)
INDICES DERIVED FROM THE CPT
-Breakpoint
-Intensity
-Pmax
-Omax
-Elasticity

10. Results
Effect of price on cigarette demand
78.7% of participants reported smoking an average of 5.07 cigarettes (SD = 6.25) even at €2 each.
A higher percentage of depressive smokers (86.2%) than non-depressed smokers (71.8%) reported the intention to keep purchasing even at a price of €2 per cigarette (χ2 = 5.174, p = .023; Cramer’s V = .177).
Smokers  with elevated depressive symptoms showed a lower elasticity score (M = 0.084, SD = 0.044) than individuals without such depressive symptomatology (M = 0.103, SD = ).

11. Results
Hierarchical multiple regressions of depression predicting CPT demand indices (controlling for smoking related measures, sex, monthly income, and anxiety).
CPT
indices
Breakpoint
Omax
Pmax
Intensity
Elasticity Β p
Cigarettes
per
day
.194
.016
.284
<.001
.220
.006
.672 -
Years of
regular
smoking
-.212
.013
-.172
.032
-.204
FTND
-.266
.001 CO
Gender
Monthly
income
.152
.068
.201
.011
.153
.056
STAI/E
STAI/R
BDI-II
.176
.034
-.159
.041
Depressive symptomatology significantly predicted both elasticity of demand and breakpoint.
Si quieres comentar algo de análisis mediacionalesWe also computed mediational analyses to test the extent to which other significant predictors of breakpoint and elasticity (cigarettes per day, years of regular smoking, FTND) could mediate the association between BDI scores and both breakpoint and elasticity. None of these nicotine dependence variables mediated the association between depressive symptomatology and cigarette demand.

12. Conclusions
Depression remained a significant predictor of elasticity of demand and breakpoint after controlling the effect of relevant covariates.
The elasticity and breakpoint indices may be the most important facets of relative reinforcing efficacy in order to understand the association between cigarette demand and depressive symptoms.
Primera conclusión: these results support previous studies showing the overlap between individual CPT demand indices (X X) and hence suggest that the five facets of the cigarette demand curve might be better represented by a reduced number of factors. The fact that significant correlations differed among groups, suggest that a different CPT´s latent structure might exist for each of them.
Segunda conclusion: The present results reflect individuals’ resistance to change their level of tobacco consumption as prices increase
Explicaciones:
1) Smoking may provide individuals with depressive symptoms with a means of self-medicating a negative state of mind  and a way to manage anhedonia making them less sensitive to raises in the cost of cigarettes. This explanation is also supported by research showing that anhedonia predicts heightened bias in the relative reward value of cigarettes over alternative reinforcers such as money.
2)Second, environmental factors such as stressful and unstable living conditions may increase nicotine intake among smokers with depressive symptoms. Also, experimental studies show that stress induced by nicotine deprivation enhances tobacco demand (Acker and MacKillop 2013; MacKillop et al. 2012).
3)Third, acute increases in negative affect may impact tobacco demand via increases in the negative reinforcing efficacy of cigarettes, thus provoking less elasticity and high breakppoint indices

13. Conclusions Clinical implications
Breakpoint and elasticity indices might contribute to predict poor treatment response and thus detecting which individuals need further assessment or treatment aid.
Incentive based approaches and behavioral activation interventions hold promise in improving abstinence rates and depression through encouraging patients to engage in pleasant alternative activities to replace smoking.
Principio segunda implicación: Smokers with elevated depressive symptoms resist reducing their tobacco consumption as prices increase, suggesting that abstinence is hindered by a heightened reinforcing value of smoking.

14. Thank you very much for your attention!