Comparing psychopathy traits and behavioral inhibition among smoker and non-smoker teenage students

Aims: Adolescence is a critical period because the brain is involved in the process of maturation that entails cognitive functions. On the way of maturation, an individual’s inhibitory control undergoes many changes and becomes vulnerable to different thrill-seeking like smoking, drinking, and so on. Smoking is highly prevalent among teenagers that are trying to take control of their behaviors in order to join society. They experience antisocial behavior too which is a trait that can lead adolescents to addiction. This trait is an inevitable part of psychopathy. Inhibitory deficits and psychopathy have been widely reported in addiction studies. The current study tried to investigate the relationship between psychopathic traits and behavioral inhibition between male smokers and non-smoker teenage students. Materials & Methods: Statistical sample of this research is 62 teenage students aged 17 years that are divided into smoker and non-smoker groups. The participants have been chosen through random sampling from the population of 10 high schools. The data have been gathered in Kordkoy and Gorgan in Golestan province. Behavioral bias has been measured by Go/NoGo task and psychopathic traits through youth psychopathic traits inventory. Also, the short form of Wechsler Adult Intelligence Scale test has been executed and used as a control variable. Preprints (www.preprints.org) | NOT PEER-REVIEWED | Posted: 11 February 2021 doi:10.20944/preprints202102.0267.v2 © 2021 by the author(s). Distributed under a Creative Commons CC BY license. Findings: A meaningful difference has been found between the performance of smoker and non-smoker groups in Go/No Go task and psychopathic traits that are smokers performed weaker in comparison with non-smokers and psychopathic traits of smokers were meaningfully higher than non-smokers. On the other hand, there was no significant difference between these two groups in their Wechsler Adult Intelligence Scale scores. Conclusion: The results have shown that smokers have higher psychopathic traits and lower behavioral inhibition when compared with their non-smoker peers. According to the results of current research, smoking can decline the cognitive functions.


Introduction
Tobacco is a ruthless and vicious murderer that takes more than 8 million people's lives each year. More than 80 percent of the tobacco users live in low-and middleincome countries (Health Organization, 2018). Addictive drugs are taken as a mood booster or intensifier by individuals like staying energetic at parties or heighten the level of happiness or relieve distress (Hyman & Malenka, 2001).
When these drugs are being used or abused recurrently and after a period of time the users experience and state of tendency and dependency to use the specific drug or a combination of drugs (Cami & Farré, 2003). This state comes with a consequence which is called addiction and symptom, or in other words, withdrawal symptoms when the drug is not available or using becomes impossible. Many studies have been shown that addiction has some partners in crime such as impaired executive (inhibitory) control over behavior, aberrant learning, and incentive-sensitization to drug use and drug cues (e.g. Robinson & Berridge 2008;Everitt &Robbins 2016;Badiani, Berridge, Heilig, Nutt, & Robinson, 2018;Volkow & Li, 2004;Vandaele & Janak, 2018).
The onset of psychoactive drug use starts during late childhood or early adolescence and occurs in a relatively predictable sequence (Kandel and Kandel, 2015). Adolescent start their drug experiment with those drugs that are available and easily accessible for adults legally like alcohol and tobacco. And the other side of the experiment goes to the path of the illegal part of drugs like marijuana and so on (Keyes, Rutherford, & Miech, 2019). According to the literature, some people test marijuana or alcohol before smoking, which states the fact that the onset and sequence of drug use happens after smoking. This hypothesis is known as the "gateway hypothesis" (Kandel, 1975), and ccording to this hypothesis, there are two opening gates for addiction, cigarettes and alcohol. There is a consensus among some researchers that tobacco use disorder (TUD) causes some damages to the modulation of cognitive processes, emotions, and reward circuit in the brain, which indicates the fact that TUD can impose long-lasting and wide changes in the brain and its circuits (Sutherland & Stein, 2018;Koob & Volkow, 2010;Kalivas, 2002;Fedota, Sutherland, Salmeron, Ross, Hong, & Stein, 2015).
Behavioral inhibition is a very well-known cognitive factor that plays a significant role in TUD (Potter, Newhouse, 2004). According to Barkley (1997), behavioral inhibition owns three components: the capacity to inhibit pre-potent (learned) responses, creating a delay in responding to an event; the capacity to interrupt ongoing responses due to performance feedback, and the protection of this delay in responding (the ability to maintain the delay in responding that was created by inhibiting the responses. To sum up, cognitive/behavioral inhibition indicates a sort of delaying impulse or urge to take action, and/or capability to abstain from responding because of surroundings cues (Potter & Newhouse, 2004). It has been shown that deficits in behavioral inhibition and its neural correlates can cause compulsive and harmful behaviors that are associated with addiction and impediment of free will (Goldstein &Volkow, 2011;Linhartová, Kuhn, Damborská, Lamoš, Mikl, Barteček, & Bareš, 2017). During adolescence, the capacity of behavioral inhibition undergoes many changes due to brain evolution and growth which means there is a constant unbalanced state of controlling or inhibiting the behavior. Another reason for this unsteady state is the expansion of prefrontal regions that are vital for behavioral inhibition (Anokhin & Golosheykin, 2016). Hence, the ability to control or inhibit the behaviors improves from late childhood to adolescence (Schachar & Logan, 1990). Mashhoon, Betts, Farmer & Lukas (2018) state that the capacity of inhibition differs between late-onset smokers, non-smokers, and early-onset smokers. The result showed that early-onset smokers made more mistakes in the inhibition part (No Go) of the Go/No Go task compared to the other two groups.
On the other hand, Riccio, Waldrop, Reynolds, Lowe (2001) observed that nicotine in non-smokers can decrease the errors in inhibition tasks. Bekker, Böcker, Van Hunsel, Van Den Berg, Kenemans (2005) reported their result contradicted the common hypothesis of declining behavioral inhibition in smokers. Therefore, they observed that nicotine actually decreases the inhibition error in the stop-signal test in the smokers' group, which means improvement of controlled performance in smokers (Bekker et al., 2005).
The tendency to smoke cigarettes and take drugs includes different reasons, and psychopathy is one of these reasons. Cleckley (1976) in his book "The Mask of Sanity" defines Psychopathy as a pervasive personality disorder. Heritage (2017) describes some fundamental features for psychopathy such as low fear, interpersonal dominance, diminished empathy, manipulation/deception, and superficial charm mixed with impulsivity, aggression, sensation/reward seeking, and increased negative emotionality. Individuals with psychopathy disorder show behavioral deviations and poor control that increases the chance of drug addiction (Heritage, 2017). Melanko, Leraas, Collins, Fields, Reynolds (2009) compared smoker and non-smoker teenagers in terms of psychopathic traits, antisocial behavior, and impulsivity. They concluded that the smoker group showed more psychopathic traits, antisocial behavior, and impulsivity than the non-smoker group. Hoffman, Jacobs, Dennis, McCready, Hickok, Smith, Kohno (2020) studied the relationship between addiction and psychopathy from the neurological and anatomical perspective. He found there are similar abnormalities in ventral striatal function and cortico-striatal resting-state functional connectivity (RSFC) both in psychopathy and addiction. And these abnormalities are responsible for criminal behavior, decision making, and impulse control. The current study aims to investigate whether behavioral inhibition and psychopathic traits differ between smoker and non-smoker groups.

Methodology
All participants were recruited from the local high schools in Gorgan City and Kordkoy City, Golestan province, Iran. 62 male teenage students were selected through a random selection from an accessible population. 32 smokers were assessed according to the DSM-5 criteria for STUD. According to these criteria, someone is considered a smoker or experiencing STUD that at least has experienced two of the mentioned criteria in the past 12 months.
Inclusion criteria for this study were male students who are 17 years old (for both groups) and having at least two criteria from DSM-5 criteria for tobacco use disorder in 12 months' time range (for the smokers' group). The exclusion criteria were severe mental disorders and cognitive deficits, subjects use cigarettes with other drugs like alcohol or marijuana, Taking Psychiatric medication, and being in medical or psychiatric interventions.

Procedure
All participants read and filled in a Consent Form. First, Go/NoGo was introduced to them, and then a trial round was performed; the main experiment performed afterward. After that, the four-subtest short version of WASI-R was explained by the researcher and performed one by one (Vocabulary, Block Design, Arithmetic, and Picture Arrangement). In the end, participants filled in the YPI questionnaire.
The whole process took 50 minutes for each participant.

Tasks
Go/No-Go task: This task is a reliable paradigm to measures response inhibition, and in many nicotine addiction studies has been used (Roberts, Rau, Lutzenberger, & Birbaumer, 1994;Kozink, Kollins & McClernon, 2010;Gießing, Thiel, Alexander-Bloch, Patel, & Bullmore, 2013;Lesage, Sutherland, Ross, Salmeron, Stein, 2020). The subject must respond to one type of these stimuli (Go), and avoid responding to another one (No-Go). Since the number and frequency of Go stimuli are more than No-Go; the subject is more probable and ready to respond than avoiding. There are two sorts of errors that are measured: first, commission errors occur when the subject is not supposed to press any keys because the No-Go stimulus is being presented (or creating false alarms). Second, omission errors occur when the subject is supposed to press a key because the Go stimulus is being presented (also known as misses). And reaction time is also measured and shows how fast or late the subject performs in a Go or No-Go situation. In the current study, a computerized version of Go/NoGo used. In the computerized version of Go/NoGo, the trial stage comes first and clarifies the instructions. According to these instructions, two rectangles appear on the screen in "one in white and the other in blue" or "white and yellow" randomly, and for a short period (0.2 sec), and you must pay attention carefully to these pair of rectangles.
If one of the rectangles is in yellow, do not press any key, but if one rectangle is in blue and appears on the right side of the screen, press "?", Come and press "z" when you see the rectangle appear on the left side of the screen. To start the process, the subject must press the "Enter" key. After the trial stage, the main stage begins that presents 40 trials for the subject.

Youth psychopathic traits inventory (YPI):
YPI is a self-report questionnaire that includes 50 items; responses are given on a 4-point Likert scale ranging from "Does not apply at all" to " Applies very well" (Andershed, Kerr, Stattin, & Evander, 2002) Wechsler (1981) found that the highest split-half reliability was for Vocabulary (.96), and the lowest split-half reliability was for Picture Arrangement (.52). Silverstein (1982) introduced two (Vocabulary and Block Design) and four subtests (Vocabulary, Block Design, Arithmetic, and Picture Arrangement) short forms of the WASI-R that is widely used in studies considering mental problems (Franzen, 2000). In a study, the correlation between four subtests short form and WAIS-R Full-Scale IQ reported highly significant (r (53)= .95). According to this result, the four subtests short form appear to have clinical utility as a screening device to identify patients with atypical cognitive functioning (Ryan, Georgemiller, & McKinney, 1984). Four subtests of WASI-R were employed to control the effect of intelligence on two groups' performances.

Results
Parametric statistics, including analysis of covariance, multivariate analysis of variance, and independent t-test, were utilized for data analysis. Therefore, the normality assumption was tested using Shapiro-wilk test, and the result showed that all the variables in the study had a normal distribution (α = 0.01). The homogeneity of variances was also examined using Levene's test, and as table 1 shows, in all variables of the study (except the behavioral inhibition), the variance of the two groups is equal. However, as the number of subjects in the two groups is equal, the heterogeneity of the two groups' variances in the behavioral inhibition variable does not pose a problem for the use of parametric tests. According to the table above, the mean of the two groups is not equal in all variables, but in order to determine whether these differences are significant or not, appropriate statistical methods must be used.
The univariate analysis of covariance was employed to compare the smoker and non-smoker groups in the inhibition score and equate the two groups in terms of intelligence quotient (IQ).
IQ scores were entered into the analysis as an auxiliary variable. The results of the covariance analysis to compare the smoker and non-smoker groups in the inhibition score are as follows. 11625.51; Sig: 0.36); hence the assumption of homogeneity of the error covariance matrix has been met. Moreover, considering the multiple statistics for comparing the smoking and non-smoking groups in the psychopathic traits, as well as the amount of Wilkes' lambda (F = 3.80; p <0.001), seemingly there is a significant difference between the two groups in terms of the linear composition of the traits of psychopathy; meaning that there is no prohibition on using multivariate analysis of variance.  Table 4, there is a significant difference between the two groups in the components of lying, manipulation, remorselessness, impulsivity, and irresponsibility. The average of the smoker group in these subscales is significantly higher than that of the non-smoker. There is no significant difference between the smokers and non-smokers groups in the other subscales (Dishonest charm, Grandiosity, unemotionality, callousness, thrill-seeking).
An independent t-test was employed to compare the two groups in the total psychopathy score, as follows: Based on table 5, there is a significant difference between smokers and nonsmokers groups in terms of the mean score of total psychopathy, and the mean of the smoking group is significantly higher than that of the non-smoking group.

Discussion
This study aimed to compare behavioral inhibition and psychopathic traits of smokers and non-smokers. By analyzing the components of Go/No-Go software that was used to measure behavioral inhibition, it was found that there is a significant difference between the two groups in terms of inhibition score, and the average inhibition score of the smoking group is significantly lower than the average inhibition score of the non-smoking group. Overall, the smoking group had a lower response inhibition than the non-smoking group.
The results of this study support the mentioned researches in the field of response inhibition. The lower level of inhibition prompts a higher rate of addiction or substance use disorder (Lilienfeld, Latzman, Watts, Smith, & Dutton, 2014).
Various studies have reported poor performance of psychopathic individuals in inhibition tests. They have shown that impaired behavioral inhibition is a hallmark of psychopathic individuals and that lack of inhibition can be one of several factors influencing the unsuccessful treatment of these individuals in the field of abstinence from addiction and criminal habits (Holland, Cousson, Patterson, Newman, 1993;Kyle, Smith, Hare, Liddell, 2000).
It was observed that there was a significant difference between the two groups in the components of lying, manipulation, remorselessness, impulsivity, irresponsibility. So the average of the smoking group in these subscales was significantly higher than the non-smoking group. Heritage (2017) states that Psychopathy disorder increases the rate of drug addiction.
Behaviors such as interpersonal violence and propensity to commit crimes are also integral to this disorder. One of the structural factors of anti-socialism is the sociopath-impulsive factor, and this factor has the highest correlation and connection with criminal behaviors, whether violently or non-violently. It is also associated with a decrease in individuals' stability of educational and professional life. It has also been shown to correlate positively with other externalizing behaviors, such as substance abuse (Anestis, Anestis, & Joiner, 2009;Verona, Sprague, & Sadeh, 2012;Walters, 2012). Individuals with high levels of sociopathimpulsive factor showed reduced neural processing in the face of non-oriented stimuli, and their dopamine levels increase when predicting a reward, and in general, their skin's electrical activity decreases in response to emotional stimuli (Benning, Patrick, & Yakonu, 2005 Behaviorally, Fearless Dominance is associated with increased thrill and sensationseeking behavior (Ross, Benning, Patrick, Thompson, and Tarston, 2009).
Given the limitations of sampling and the lack of an extensive age and gender distribution, it is recommended that in future research in the scope of psychopathy and addiction, age and gender diversity should be considered. On the one hand, by using software designed exclusively for investigating addiction, the results will be obtained in a more specialized way, and it is suggested using software made for specific purposes. On the other hand, by using different techniques, such as biomarkers and Eye tracker, accompanied by cognitive tests, the results can be delivered to other researchers with higher quality. Furthermore, the use of state-ofthe-art technologies such as fMRI can help to provide a deeper understanding of the brain and behavioral structures while performing cognitive tests.