Research of the study of decision making processes in tattooed and non-tattooed women as detailed earlier  entailed recruitment through a variety of arenas – social networks (Facebook), notices at the university, and word of mouth. The study was approved by the review board at Bar Ilan University (Ramat Gan, Israel). NPI and BIS-11 scales  were used to analyze women only, thus avoiding gender differences.
Participants from both research [39 smokers aged 18-35 (M-27.4, SD=5.59)] and control [81 non-smokers age ranged 18-35 (M=28.9, SD=5.68) groups were all from the Tel Aviv area, with similar socioeconomic backgrounds and were employed, or students (high school diploma or lower, BA, MA ) or graduates.
Each participant attended an individual session (up to an hour and a half) that included a detailed explanation about the study, its and its aims and then were asked to sign an informed consent form.
All candidates underwent an interview to give researchers insight into their medical and psychiatric history, as well as their backgrounds and family life. Tattooed participants citing addictions (drug and alcohol abuse or dependence) other than cigarette smoking or psychiatric disorders (requiring treatment and/or medication), and on-tattooed women citing current or past DSM-IV-TR axis I psychiatric disorders were excluded from the study.
Over a five month period, participants volunteered and in lieu of payment were given a free psychological consultation and a professional assessment of their personality traits.
Narcissistic Personality Inventory (NPI)
A measure that is recognized and used often to study personality psychology in narcissism is a 40 item measure (M=17.85, SD=7.6, α = 5.86) , known as NPI, which has been corroborated based on the use of a wide array of criteria . Based on the DSM-related definition, Narcissism is defined as a continuum with extreme manifestations representing pathological narcissism, while the less extreme forms indicate nonclinical narcissistic personality traits . NPI is a mix of both adaptive and maladaptive content connected to psychological resilience on one hand, and impaired personal relationships on the other .
All NPI scales were required as the total scores are a compilation of all the responses to the various items , encompassing various dimensions of personality. To this end, seven NPI scales – authority, exhibitionism, superiority, vanity, exploitativeness, entitlement and self-sufficiency  – were applied.
The reliability of the full scale internally is .83, with 7 subscale reliabilities of .50-.73 . The full scale after 13 weeks has high test-retest reliability (r = .81), with the test-retest on the subscales being lower (range: .57 to .80) . In the Hebrew version of the questionnaire that was developed , analysis of the normative population demonstrated similar findings to the English questionnaire. Cronbach's alpha was used to test the accuracy of the Hebrew version – 0.9 – and the validity scale was 0.88 .
Barratt Impulsiveness Scale -Eleven Edition (BIS-11)
This 30-item self-report measures impulsiveness yielding three subscales and a total score , is the most commonly used in both research and clinical settings . The 30 statements are assessed by participants using a 4-point Likert scale that ranges from 1-4: 1= never/rarely, 2=sometimes, 3=frequently and 4=almost always/always.
The total scores range from 30-120. A higher total score indicates a higher self-reported level of impulsivity.
The 3 subscales, or Motor Impulsiveness (MI), reflect action without any forethought ("I do things without thinking"; 11 items; α = 5.52), Attentional Impulsiveness (AI), which reflects a reduced ability to maintain attention toward a stimulus ("I concentrate easily"; 8 items; α = 5.66), and Non-Planning Impulsiveness (N-PI), which reflects an emphasis on the present ("I plan tasks carefully"; 11 items; α = 5.66); 
Data were analyzed using SAS 9.1 software for Windows. All analyses used two-tailed levels of significance. In the first stage, the parametric (t-test) tests were performed to compare group differences in demographic and personality characteristics. In the second stage the multivariate logistic regression analysis was performed to assess the relationship between smoking and significant variables identified in the first stage.
Multivariate logistic regression models were built using backward variable selection techniques, considering variables with a univariate p-value≤0.25  as potential independent risk factors. A p-value of less than 0.05 was considered statistically significant. The odds ratios (OR) with 95% confidence intervals (CI) were assessed for each predictor. A c-index was calculated to evaluate model discrimination, and the Hosmer-Lemeshow test was applied to evaluate model calibration.