Like an R2 value for least squares regression, higher AUC-ROC values reflect better prediction and are interpreted as the probability of correctly identifying an individual as DS (vs. ITS) based upon dependence score. Thus, AUC-ROC ranges from 0.5 (random guessing) to 1.0 (perfect prediction; Hanley & McNeil, 1982). Dependence selleck chemicals Dorsomorphin and Smoking Behavior Within ITS, we assessed the relationship between dependence and smoking behaviors by running separate least square regression models for each dependence measure, examining linear and quadratic effects of smoking behavior on each dependence measure. All analyses controlled for history of daily smoking (CITS or NITS); models that did not control for smoking history yielded virtually identical results.

Results Differences in Dependence Between ITS and DS ITS were significantly less dependent than DS on every measure of dependence (Table 1). The differences were very large, as seen in the steep slopes of the logistic functions in Figure 1. Three measures (NDSS, FTND, and WISDM Primary) yielded AUC-ROC values greater than or equal to .90��that is, the measures correctly differentiated ITS from DS more than 90% of the time. When scored dichotomously, the HONC classified all DS and 93% of ITS as dependent, yielding the lowest AUC-ROC value (0.54). However, the continuous HONC achieved an AUC-ROC of 0.81. Table 1. Differences in Dependence Between Daily Smokers (DS) and Intermittent Smokers (ITS) and Also Within ITS Figure 1.

Differences in dependence measures Fagerstr?m Test for Nicotine Dependence (FTND), time to first cigarette (TTFC), Nicotine Dependence Syndrome Scale (NDSS), Wisconsin Inventory of Smoking Dependence Motives (WISDM) Primary, WISDM Secondary, Hooked … On every measure except TTFC, CITS were more dependent than NITS but the effects were more modest, with AUC-ROC values in the .60�C.70 range (Table 1) and as illustrated by the less-steep curves in Figure 1. The HONC classified 87% of NITS and 97% of CITS as dependent, yielding a modest AUC-ROC of 0.56, but was the most discriminating measure (AUC-ROC = 0.70) when scored continuously. Relationship Between Dependence Measures and Smoking Behavior Among ITS All the dependence measures showed some variation within ITS (Table 1). Continuous HONC scores spanned the entire range of the scale, and WISDM scores nearly did so as well.

TTFC ranged from 0 min (smoking Carfilzomib immediately upon waking) to 20 hr. When ITS�� NDSS scores are considered as z-scores and evaluated as percentiles against the published normative sample (Shiffman et al., 2004), ITS�� scores ranged from the 0.1th to the 94th percentile. There was also substantial variation in ITS smoking behavior as recorded in EMA. Mean CPD (on days smoked) averaged 3.48 (SD = 2.36) cigarettes, but ranged from 1 to 17.5 CPD. The maximum CPD averaged 7.69 (SD = 5.61), ranging from 1 to 32 CPD. These two metrics were highly correlated, r = .86.