The relationship between level of cigarette consumption and latency to the onset of retrospectively reported withdrawal symptoms

A reduction in cigarette smoking improves health-related quality of life and does not worsen psychiatric symptoms in individuals with serious mental illness

INTRODUCTION

Individuals with serious mental illness (SMI) smoke cigarettes at a much higher rate than the general population, increasing their risk for medical illnesses and mortality. However, individuals with SMI do not get enough support to quit smoking, partially because of concerns from medical providers that reducing smoking may worsen their symptoms or quality of life.

METHODS

Veterans with SMI and nicotine dependence (n = 178) completed a 12-week smoking cessation trial (parent trial dates: 2010-2014) including assessments of smoking status, psychiatric symptoms (Brief Psychiatric Rating Scale), and quality of life (Lehman Quality of Life Interview-Short Version) at up to four time points: baseline, post-treatment, three-month follow-up, and 9-month follow-up. Bayesian multilevel modeling estimated the impact of changes in the self-reported number of cigarettes per day in the past seven days on psychiatric symptoms and quality of life.

RESULTS

Between subjects, each additional pack of cigarettes smoked per day was associated with a 0.83 point higher score (95%CI: 0.03 to 1.7) on a negative symptoms scale ranging from 0 to 35. Within subjects, each one-pack reduction in the number of cigarettes smoked per day was associated with an improvement of 0.32 (95%CI = 0.12 to 0.54) on the health-related quality of life scale, which ranges from 0 to 7 points. There were no other significant between- or within-subjects effects of smoking on psychiatric symptoms or quality of life.

CONCLUSIONS

Individuals with SMI and their providers should pursue smoking cessation without fear of worsening psychiatric symptoms or quality of life.

Time-dependent affective disturbances in abstinent patients with methylphenidate use disorder

BACKGROUND

Methylphenidate (MPH), also called Ritalin, is used to treat attention-deficit hyperactivity disorder (ADHD) patients. With occasional reports of subjects suffering from Methylphenidate use disorder (MPHUD), few studies analyzed the neuropsychological changes in this population.

PURPOSE

This study aims to evaluate the clinical outcomes of individuals with MPHUD.

METHODS

We retrospectively analyzed 61 MPH patients (aged 16-27 years) admitted to the Beijing Gaoxin Hospital drug rehabilitation program from Jan 2017 to Mar 2019. The drug use history and drug abuse motivation scale were collected at admission. Clinicians rated the Hamilton Depression Rating Scale, Hamilton Anxiety Rating Scale, and DSM-5 Stimulant use disorder criteria each week during the 4 weeks rehabilitation program. Correlation analyses were conducted between drug use history and affective disturbances.

RESULTS

The results showed that the adolescent period is the peak for MPH exposure, and 1/3 of patients got their first exposure to MPH from their parents. MPH abstinence accompanies severe anxiety and depression symptoms, significantly alleviating after four weeks of treatment.

CONCLUSIONS

MPHUD is associated with substantial affective disturbances, which warrants a more considerable sample investigation.

Lebanese Waterpipe Dependence Scale (LWDS-11) validation in a sample of Lebanese adolescents

Background

Salameh et al. developed the Lebanese Waterpipe Dependence Scale (LWDS-11) that assesses nicotine dependence among adult waterpipe smokers. In view of the high waterpipe use among Lebanese youth and other neighboring countries, it was deemed necessary to check the psychometric properties of the LWDS-11, originally adapted to the Lebanese population, to measure nicotine dependence among adolescents.

Methods

Two cross-sectional investigations were conducted; Study 1 (January and May 2019) enrolled a total of 449 students who were exclusive waterpipe smokers; this sample was used to conduct the exploratory factor analysis. Study 2 enrolled another sample composed of 243 waterpipe smoking adolescents. This sample was independent from the first one and was used to conduct the confirmatory analysis.

Results

The results also showed that 312 (69.5%) [95% CI 0.652–0.738] had high waterpipe dependence (scores of ≥10). Results of the factor analysis in sample 1 showed that all LWDS-11 items were extracted following the factor analysis. Items converged over a solution of one factor; total variance explained = 70.45%, α_Cronbach = 0.96). The results of the confirmatory factor analysis were as follows: the Maximum Likelihood Chi-Square = 129.58 and Degrees of Freedom = 45, which gave a χ²/df = 2.88. For non-centrality fit indices, the Steiger-Lind Root Mean Square Error of Approximation (RMSEA) was 0.08 [0.071–0.106]. Moreover, the Comparative Fit Index (CFI) value was 0.77.

Conclusion

The preliminary results suggest that the LWDS-11 has good psychometric properties to measure waterpipe dependence among adolescents. We hope this tool would serve the benefit of research and epidemiology.

Smoking Cessation in Adolescents: targeted approaches that work

Smoking Cessation in adolescents can be considered in a developmental context to enable the clinician to individualise the appropriate assessment and management of the young person they are seeing whether it is in a primary or tertiary care setting. Adolescence is a time of rapid neurocognitive and hormonal change with these factors affected by personality and behavioural factors as well as family, cultural and psychosocial context. Adolescents are uniquely vulnerable to smoking initiation and nicotine addiction throughout these years. Increased awareness of the risks of smoking and using opportunities to assess and intervene regarding smoking cessation are integral to clinical practice for all clinicians seeing young people. This review will discuss the demographics of adolescent smoking, risk factors, assessing smoking and nicotine addiction, the importance of brief interventions, the evidence base for appropriate interventions, particularly in high risk groups and will emphasise innovative training for health professionals in adolescent smoking cessation.

Stages of physical dependence in New Zealand smokers: Prevalence and correlates

BACKGROUND

Physically dependent smokers experience symptoms of wanting, craving or needing to smoke when too much time has passed since the last cigarette. There is interest in whether wanting, craving and needing represent variations in the intensity of a single physiological parameter or whether multiple physiological processes may be involved in the developmental progression of physical dependence.

AIM

Our aim was to determine how a population of cigarette smokers is distributed across the wanting, craving and needing stages of physical dependence.

METHODS

A nationwide survey of 2594 New Zealanders aged 15years and over was conducted in 2014. The stage of physical dependence was assessed using the Levels of Physical Dependence measure. Ordinal logistic regression analysis was used to assess relations between physical dependence and other variables.

RESULTS

Among 590 current smokers (weighted 16.2% of the sample), 22.3% had no physical dependence, 23.5% were in the Wanting stage, 14.4% in the Craving stage, and 39.8% in the Needing stage. The stage of physical dependence was predicted by daily cigarette consumption, and the time to first cigarette, but not by age, gender, ethnicity or socioeconomic status.

CONCLUSION

Fewer individuals were in the craving stage than either the wanting or needing stages. The resulting inverted U-shaped curve with concentrations at either extreme is difficult to explain as a variation of a single biological parameter. The data support an interpretation that progression through the stages of wanting, craving and needing may involve more than one physiological process.

WHAT THIS RESEARCH ADDS

Physical dependence to tobacco develops through a characteristic sequence of wanting, craving and needing which correspond to changes in addiction pathways in the brain. It is important to neuroscience research to determine if the development of physical dependence involves changes in a single brain process, or multiple processes. Our data suggests that more than one physiologic process is involved in the progression of physical dependence.

Can tobacco dependence provide insights into other drug addictions?

Within the field of addiction research, individuals tend to operate within silos of knowledge focused on specific drug classes. The discovery that tobacco dependence develops in a progression of stages and that the latency to the onset of withdrawal symptoms after the last use of tobacco changes over time have provided insights into how tobacco dependence develops that might be applied to the study of other drugs.As physical dependence on tobacco develops, it progresses through previously unrecognized clinical stages of wanting, craving and needing. The latency to withdrawal is a measure of the asymptomatic phase of withdrawal, extending from the last use of tobacco to the emergence of withdrawal symptoms. Symptomatic withdrawal is characterized by a wanting phase, a craving phase, and a needing phase. The intensity of the desire to smoke that is triggered by withdrawal correlates with brain activity in addiction circuits. With repeated tobacco use, the latency to withdrawal shrinks from as long as several weeks to as short as several minutes. The shortening of the asymptomatic phase of withdrawal drives an escalation of smoking, first in terms of the number of smoking days/month until daily smoking commences, then in terms of cigarettes smoked/day.The discoveries of the stages of physical dependence and the latency to withdrawal raises the question, does physical dependence develop in stages with other drugs? Is the latency to withdrawal for other substances measured in weeks at the onset of dependence? Does it shorten over time? The research methods that uncovered how tobacco dependence emerges might be fruitfully applied to the investigation of other addictions.

Levels of physical dependence on tobacco among adolescent smokers in Cyprus

PURPOSE

The purpose of this study is to assess tobacco dependence among Cypriot adolescents and examine its association to cigarette consumption and attitudes towards smoking.

METHODS

The current study used cross-sectional data from the 2011 Cyprus Global Youth Tobacco Survey which adopted multistage cluster sampling methods to select adolescents registered in middle and high schools in Cyprus. Tobacco use, physical dependence on tobacco, and attitudes towards tobacco use were measured in 187 adolescents aged 13-18years old who reported that they had smoked at least once in the preceding 30days. Physical dependence was assessed using the Levels of Physical Dependence scale.

RESULTS

Physical dependence was present in 86% of the adolescent smokers. The mean latency to needing among smokers in the highest dependence group was 101h. Significant associations were observed between physical dependence and the perceived difficulty in quitting (OR=13.1, 95% CI: 4.0, 43.0) as well as the expectation to continue smoking for the next five years (OR=3.3, 95% CI: 1.3, 8.4). Significant associations were also observed between physical dependence and the number of smoking days per month, daily smoking, daily cigarette consumption, lifetime cigarette consumption, and perceived difficulty in abstaining from smoking for one week.

CONCLUSIONS

Physical dependence provides a symptom-based approach to assess dependence and it is a strong predictor of adolescents' perceptions of their ability to quit or to refrain from smoking for a week. Physical dependence on tobacco was highly prevalent among adolescent smokers in Cyprus and it was associated with greater perceived difficulty in quitting. Interventions targeting adolescent smoking must account for the high prevalence of physical dependence.

Nondaily smokers' experience of craving on days they do not smoke

Nondaily, or intermittent smokers (ITS), represent a growing pattern in adult smoking that needs to be explained by models of drug dependence. ITS regularly and voluntarily abstain from smoking, yet have difficulty quitting. We examine potential accounts of ITS' smoking by exploring their experience of craving and withdrawal on the days they abstain. For 3 weeks, 146 ITS and 194 daily smokers used the Ecological Momentary Assessment (EMA) to monitor craving, withdrawal, and smoking in real-time. ITS' craving (p < .001) and arousal (p < .001) were significantly lower on the 34.4% of days when they abstained (compared with days they smoked), and they experienced no increases in withdrawal symptoms. ITS who abstained for longer experienced lower craving, even on their first day of abstinence (p < .001). Within strata defined by longest duration of abstinence (1, 2-3, 4-6, ≥7 days), craving did not change over time, demonstrating no increase as resumption of smoking approached. Craving increased only at the moment smoking resumed. Furthermore, duration of abstinence runs varied more within persons than across persons. These findings contradict the predictions of a model positing that craving recurs at fixed intervals. Findings are consistent with the hypothesis that ITS' smoking is cued or primed by particular stimuli rather than by temporal cycles. These analyses demonstrate that ITS do not experience increased craving or withdrawal on days they do not smoke, and show neither signs of classical dependence nor regular cycles of craving and smoking.

What aspect of dependence does the fagerström test for nicotine dependence measure?

Although the Fagerström Test for Nicotine Dependence (FTND) and the Heaviness of Smoking Index (HSI) are widely used, there is a uncertainty regarding what is measured by these scales. We examined associations between these instruments and items assessing different aspects of dependence. Adult current smokers (n = 422, mean age 33.3 years, 61.9% female) completed a web-based survey comprised of items related to demographics and smoking behavior plus (1) the FTND and HSI; (2) the Autonomy over Tobacco Scale (AUTOS) with subscales measuring Withdrawal, Psychological Dependence, and Cue-Induced Cravings; (3) 6 questions tapping smokers' wanting, craving, or needing experiences in response to withdrawal and the latency to each experience during abstinence; (4) 3 items concerning how smokers prepare to cope with periods of abstinence. In regression analyses the Withdrawal subscale of the AUTOS was the strongest predictor of FTND and HSI scores, followed by taking precautions not to run out of cigarettes or smoking extra to prepare for abstinence. The FTND and its six items, including the HSI, consistently showed the strongest correlations with withdrawal, suggesting that the behaviors described by the items of the FTND are primarily indicative of a difficulty maintaining abstinence because of withdrawal symptoms.

Neuroadaptation in nicotine addiction: update on the sensitization-homeostasis model

The role of neuronal plasticity in supporting the addictive state has generated much research and some conceptual theories. One such theory, the sensitization-homeostasis (SH) model, postulates that nicotine suppresses craving circuits, and this triggers the development of homeostatic adaptations that autonomously support craving. Based on clinical studies, the SH model predicts the existence of three distinct forms of neuroplasticity that are responsible for withdrawal, tolerance and the resolution of withdrawal. Over the past decade, many controversial aspects of the SH model have become well established by the literature, while some details have been disproven. Here we update the model based on new studies showing that nicotine dependence develops through a set sequence of symptoms in all smokers, and that the latency to withdrawal, the time it takes for withdrawal symptoms to appear during abstinence, is initially very long but shortens by several orders of magnitude over time. We conclude by outlining directions for future research based on the updated model, and commenting on how new experimental studies can gain from the framework put forth in the SH model.

A comparison of the autonomy over tobacco scale and the Fagerström test for nicotine dependence

The autonomy over tobacco scale (AUTOS) is a 12-item theory-based instrument used to measure tobacco dependence in smokers. It provides separate measures of three factors that make smoking cessation more difficult: withdrawal symptoms, psychological dependence, and cue-induced urges to use tobacco. We compared the internal reliability and concurrent validity of the AUTOS to those of the Fagerström test for nicotine dependence (FTND). Adult current smokers (n=422; 62% female; 86.8% white; mean age 33.3 years, SD=13.7; 57% daily smokers) completed an anonymous web-based survey that included the AUTOS, the FTND and 11 smoking-related behavioral measures. Cronbach's α was .94 for the AUTOS and α>.75 for each of the 3 subscales; α=.73 for the FTND. The AUTOS and its subscales correlated with all measures of concurrent validity (r=.70 between AUTOS & FTND). The AUTOS correlated better than the FTND with the Hooked on Nicotine Checklist, the longest period of abstinence, latency to wanting, percentage of time a person smokes because of momentary need, pleasure from smoking, days smoked per month, and concern about deprivation. The measures showed similar correlations with the latencies to craving and needing. The FTND correlated better with the duration of smoking and cigarettes smoked per day. Based on these results and those from prior studies, we conclude that the AUTOS offers researchers a valid and highly reliable, theory-based measure that is more versatile in its applications than the FTND.

Does progression through the stages of physical addiction indicate increasing overall addiction to tobacco?

RATIONALE

With physical addiction to tobacco, abstinence triggers a desire to smoke. As physical addiction advances, the desire to smoke changes in quality and intensity from wanting, to craving, to needing. A prior study in adolescents suggested that this progression signifies increasing addiction.

OBJECTIVE

We sought to determine if the sequential appearance of wanting, craving and needing provides an indication of the intensity of other markers of tobacco addiction including psychological and behavioral indicators.

METHODS

A web-based survey was completed by 422 smokers ages 18-78 years. Subjects were assigned to one of four qualitatively distinct stages of physical addiction based on their most advanced symptom: 1-none, 2-wanting, 3-craving, or 4-needing. Using linear Chi square and ANOVA, we determined if higher stages were associated with higher levels of tobacco addiction on more than a dozen measures.

RESULTS

16.8% of subjects were in stage 1, 26.1% in stage 2, 17.1% in stage 3 and 40.0% in stage 4. Each step up in stage was associated with higher levels of addiction as measured by the Fagerström Test for Nicotine Dependence, the Hooked on Nicotine Checklist, the Autonomy over Tobacco Scale, and higher levels of psychological dependence, duration of tobacco use, frequency of tobacco use, daily cigarette consumption, and 10 additional measures.

CONCLUSIONS

In this cross-sectional study, each sequential stage of physical addiction was associated with higher levels of every indicator of addiction. The data suggest that the stages of progression of physical addiction provide a global indication of the severity of tobacco addiction.

An evaluation of a clinical approach to staging tobacco addiction

OBJECTIVES

To determine whether adolescents' symptom reports are consistent with the developmental sequence of tobacco addiction and whether the sequential appearance of these symptoms signifies increasing addiction.

STUDY DESIGN

An anonymous survey was administered to 349 tobacco users in grades 9 through 12 in Florida. The combinations of withdrawal symptoms reported were examined to determine whether they were consistent with the developmental sequence described by case reports (wanting, then craving, then needing). Dependence was measured by several validated measures, including the Hooked on Nicotine Checklist, the Autonomy Over Tobacco Scale, and the modified Fagerström Tolerance Questionnaire.

RESULTS

The combinations of withdrawal symptoms reported by 99.4% of subjects were consistent with case reports stating that wanting, craving, and needing develop in that sequence. Across the stages, from wanting to needing, higher stages were associated with significant increases in the strength of addiction as measured by the Hooked on Nicotine Checklist, the Autonomy Over Tobacco Scale, the modified Fagerström Tolerance Questionnaire, and all other measures.

CONCLUSIONS

Our data confirmed that withdrawal symptoms develop in an orderly sequence, as proposed, and indicate that each progressive step along the sequence of wanting, craving, and needing represents a substantial increase in tobacco addiction. This provides the foundation for a clinical approach to staging the progression of tobacco addiction.

Development of a measure of the latency to needing a cigarette

PURPOSE

People addicted to smoking experience a recurrent physiologic need to smoke anytime when they go too long without smoking. Our purpose was to evaluate the reliability and concurrent validity of a measure of the time elapsed between completion of smoking one cigarette and experiencing the need to smoke another (the latency to needing a cigarette-LTNC). We also investigated the relationship between the LTNC and dependence-related symptoms.

METHODS

An anonymous, self-administered survey was completed by 134 current adolescent smokers, and in a separate study, 32 smokers were asked to complete a retest.

RESULTS

A frequent need to smoke was reported by 84.3% of the current smokers. Consistent with published case histories, the duration of the LTNC varied widely between the individuals. Among subjects who reported a regular need to smoke, 48% reported that their LTNC had shortened over time. The median LTNC among subjects who had smoked <100 cigarettes was 243 hours as compared with 2 hours for those who had smoked ≥ 100 cigarettes (p < .001). Test-retest reliability was reported to be excellent (r = .85, p < .001). As expected, LTNC correlated moderately and inversely with daily cigarette consumption (ρ = -.53, p < .001). It also correlated inversely with cue-induced craving (ρ = -.64, p < .001), psychological reliance on cigarettes (ρ = -.43, p < .001), nicotine withdrawal (ρ = -.57, p < .001), and pleasure obtained from smoking (ρ = -.39, p < .001).

CONCLUSION

The data obtained in this study support the reliability and concurrent validity of the LTNC measure.

Thwarting science by protecting the received wisdom on tobacco addiction from the scientific method

In their commentary, Dar and Frenk call into question the validity of all published data that describe the onset of nicotine addiction. They argue that the data that describe the early onset of nicotine addiction is so different from the conventional wisdom that it is irrelevant. In this rebuttal, the author argues that the conventional wisdom cannot withstand an application of the scientific method that requires that theories be tested and discarded when they are contradicted by data. The author examines the origins of the threshold theory that has represented the conventional wisdom concerning the onset of nicotine addiction for 4 decades. The major tenets of the threshold theory are presented as hypotheses followed by an examination of the relevant literature. Every tenet of the threshold theory is contradicted by all available relevant data and yet it remains the conventional wisdom. The author provides an evidence-based account of the natural history of nicotine addiction, including its onset and development as revealed by case histories, focus groups, and surveys involving tens of thousands of smokers. These peer-reviewed and replicated studies are the work of independent researchers from around the world using a variety of measures, and they provide a consistent and coherent clinical picture. The author argues that the scientific method demands that the fanciful conventional wisdom be discarded and replaced with the evidence-based description of nicotine addiction that is backed by data. The author charges that in their attempt to defend the conventional wisdom in the face of overwhelming data to the contrary, Dar and Frenk attempt to destroy the credibility of all who have produced these data. Dar and Frenk accuse other researchers of committing methodological errors and showing bias in the analysis of data when in fact Dar and Frenk commit several errors and reveal their bias by using a few outlying data points to misrepresent an entire body of research, and by grossly and consistently mischaracterizing the claims of those whose research they attack.

A systematic review of the International Classification of Diseases criteria for the diagnosis of tobacco dependence

Our objective was to examine the evidence concerning the validity and reliability of the International Classification of Diseases criteria for tobacco dependence (ICD-TD). A literature search was conducted of 16 databases using the search terms addiction, cigarettes, Diagnostic and Statistical Manual of Disease, DSM, dependence, International Classification of Diseases, ICD, nicotine, smoking and tobacco. The search produced 37 relevant articles. We found no data supporting the predictive validity of the criteria, and none supporting the characterization of dependence as having a three-symptom threshold. We found no data concerning the validity or reliability of the official instrument, which inappropriately excludes nondaily smokers from being evaluated for dependence. We found no evidence that the ICD-TD diagnosis had been used for clinical decision making, in a smoking cessation study, or for longitudinal epidemiological surveillance. We contrast the utility of the ICD-TD criteria to an approach of diagnosing tobacco addiction on the basis of a single criterion of a compulsion to use tobacco.

A systematic review of the Diagnostic and Statistical Manual diagnostic criteria for nicotine dependence

The Diagnostic and Statistical Manual diagnostic criteria for nicotine dependence (DSM-ND) are based on the proposition that dependence is a syndrome that can be diagnosed only when a minimum of 3 of the 7 proscribed features are present. The DSM-ND criteria are an accepted research measure, but the validity of these criteria has not been subjected to a systematic evaluation. To systematically review evidence of validity and reliability for the DSM-ND criteria, a literature search was conducted of 16 national and international databases. Each article with original data was independently reviewed by two or more reviewers. In total, 380 potentially relevant articles were examined and 169 were reviewed in depth. The DSM-ND criteria have seen wide use in research settings, but sensitivity and specificity are well below the accepted standards for clinical applications. Predictive validity is generally poor. The 7 DSM-ND criteria are regarded as having face validity, but no data support a 3-symptom ND diagnostic threshold, or a 4-symptom withdrawal syndrome threshold. The DSM incorrectly states that daily smoking is a prerequisite for withdrawal symptoms. The DSM shows poor to modest concurrence with all other measures of nicotine dependence, smoking behaviors and biological measures of tobacco use. The data support the DSM-ND criteria as a valid measure of nicotine dependence severity for research applications. However, the data do not support the central premise of a 3-symptom diagnostic threshold, and no data establish that the DSM-ND criteria provide an accurate diagnosis of nicotine dependence.

Nicotine exposure during adolescence induces a depression-like state in adulthood

There is a strong link between tobacco consumption and mood disorders. It has been suggested that afflicted individuals smoke to manage mood, however, there is evidence indicating that tobacco consumption can induce negative mood. This study was designed to investigate whether nicotine exposure during adolescence influences emotionality/behavioral functioning later in life. Adolescent (postnatal days, PD 30-44) male rats were treated with twice-daily injections of nicotine (0, 0.16, 0.32, or 0.64 mg/kg) for 15 consecutive days, and their behavioral reactivity to various behavioral paradigms (the elevated plus maze (EPM), sucrose preference, locomotor activity in the open field, and forced swim test (FST) was assessed 24 h (short term) or 1-month (long term) after exposure. Separate groups of adult rats received nicotine (0.32 mg/kg) to control for age-dependent effects. We report that nicotine exposure during adolescence-but not adulthood-leads to a depression-like state manifested in decreased sensitivity to natural reward (sucrose), and enhanced sensitivity to stress- (FST) and anxiety-eliciting situations (EPM) later in life. Our data show that behavioral dysregulation can emerge 1 week after drug cessation, and that a single day of nicotine exposure during adolescence can be sufficient to precipitate a depression-like state in adulthood. We further demonstrate that these deficits can be normalized by subsequent nicotine (0.32 mg/kg) or antidepressant (ie fluoxetine or bupropion; 10 mg/kg) treatment in adulthood. These data suggest that adolescent exposure to nicotine results in a negative emotional state rendering the organism significantly more vulnerable to the adverse effects of stress. Within this context, our findings, together with others indicating that nicotine exposure during adolescence enhances risk for addiction later in life, could serve as a potential model of comorbidity.

The latency to the onset of nicotine withdrawal: a test of the sensitization-homeostasis theory

The latency to withdrawal (LTW) is the expired time between the last cigarette and when the smoker feels the need to smoke again. The sensitization-homeostasis theory predicts that the LTW is inversely related to the frequency and duration of smoking such that more frequent cigarette consumption and a longer history of tobacco use will be associated with a shorter LTW. An anonymous cross-sectional survey of 1055 10th and 11th grade students of mixed ethnicity was conducted in two schools using self-completed questionnaires. Participants were asked "After you have smoked a cigarette, how long can you go before you feel you need to smoke again?" Of 162 current smokers, 73.5% reported a regular need to smoke and a LTW. Reported values for the LTW ranged from .05 h to "3 weeks or more." Monthly cigarette consumption ranged from 1 to 895. The LTW correlated inversely with monthly cigarette consumption (Kendall's tau b=-.53, P<.001) and the duration of smoking (Kendall's tau b=-.25, P<.001) as predicted by the sensitization-homeostasis theory.

A within-subject comparison of withdrawal symptoms during abstinence from cannabis, tobacco, and both substances

A cannabis withdrawal syndrome has been characterized, but its clinical significance remains uncertain. One method of assessing the significance of cannabis withdrawal is to compare it directly to an established withdrawal syndrome. The present study was a within-subject comparison of cannabis, tobacco, and combined cannabis and tobacco withdrawal among users of both substances. Participants (N=12) completed three 5-day periods of abstinence in a randomized order, separated by 9-day periods of usual substance use. Overall withdrawal severity associated with cannabis alone and tobacco alone was of a similar magnitude. Withdrawal during simultaneous cessation of both substances was more severe than for each substance alone, but these differences were of short duration and substantial individual differences were noted. These results are consistent with other evidence suggesting cannabis withdrawal is clinically important and warrants detailed description in the DSM-V and ICD-11. Additional research is needed to replicate these findings and to further investigate the effects of abstaining from multiple drugs simultaneously.