Is impulsivity related to attentional bias in cigarette smokers? An exploration across levels of nicotine dependency and deprivation

Research has largely focused on how attentional bias to smoking-related cues and impulsivity independently influence the development and maintenance of cigarette smoking, with limited exploration of the relationship between these mechanisms. The current experiments systematically assessed relationships between multiple dimensions of impulsivity and attentional bias, at different stages of attention, in smokers varying in nicotine dependency and deprivation. Nonsmokers (NS; n  = 26), light-satiated smokers (LS; n  = 25), heavy-satiated smokers (HS; n  = 23) and heavy 12-hour nicotine-deprived smokers (HD; n  = 30) completed the Barratt Impulsivity Scale, delayed discounting task, stop-signal task, information sampling task and a visual dot-probe assessing initial orientation (200 ms) and sustained attention (2000 ms) toward smoking-related cues. Sustained attention to smoking-related cues was present in both HS and LS, while initial orientation bias was only evident in HS. HS and LS also had greater levels of trait motor and nonplanning impulsivity and heightened impulsive choice on the delay discounting task compared with NS, while heightened trait attentional impulsivity was only found in HS. In contrast, in HD, nicotine withdrawal was associated with no attentional bias but heightened reflection impulsivity, poorer inhibitory control and significantly lower levels of impulsive choice relative to satiated smokers. Trait and behavioral impulsivity were not related to the extent of attentional bias to smoking-related cues at any stage of attention, level of nicotine dependency or state of deprivation. Findings have both clinical and theoretical implications, highlighting the unique and independent roles impulsivity and attentional bias may play at different stages of the nicotine addiction cycle.

The acute effects of cannabis, with and without cannabidiol, on attentional bias to cannabis related cues: a randomised, double-blind, placebo-controlled, cross-over study

RATIONALE

Attentional bias to drug-related stimuli is hypothesised to contribute towards addiction. However, the acute effects of Δ9-tetrahydrocannabinol (THC) on attentional bias to cannabis cues, the differential response in adults and adolescents, and the moderating effect of cannabidiol (CBD) are unknown.

OBJECTIVES

Our study investigated (1) the acute effects of vaporised cannabis on attentional bias to cannabis-related images in adults and adolescents and (2) the moderating influences of age and CBD.

METHODS

We conducted a randomised, double-blind, placebo-controlled, cross-over study where three weight-adjusted vaporised cannabis preparations: 'THC' (8 mg THC for a 75-kg person), 'THC + CBD' (8 mg THC and 24 mg CBD for a 75-kg person) and PLA (matched placebo). Cannabis was administered on 3 separate days to 48 participants, who used cannabis 0.5-3 days/week: 24 adolescents (12 females, aged 16-17) and 24 adults (12 females, aged 26-29). Participants completed a visual probe task with cannabis cues. Our primary outcome was attentional bias to cannabis stimuli, measured using the differential reaction time to a cannabis vs. neutral probe, on 200-ms trials.

RESULTS

In contrast to hypotheses, attention was directed away from cannabis cues on placebo, and there was a main effect of the drug (F(2,92) = 3.865, p = 0.024, η2p = 0.077), indicating THC administration eliminated this bias. There was no significant impact of CBD nor an age-by-drug interaction.

CONCLUSIONS

Acute THC intoxication eliminated attentional bias away from cannabis cues. There was no evidence of differential response in adolescents compared to adults and no evidence that a moderate vaporised dose of CBD altered the impact of cannabis on attentional bias.

TRIAL REGISTRATION

This study was listed with the US National Library of Medicine and registered on ClinicalTrials.gov, URL: Do Adolescents and Adults Differ in Their Acute Response to Cannabis?-Full Text View-ClinicalTrials.gov, registration number: NCT04851392.

Modulation of Attentional Bias to Drug and Affective Cues by Therapeutic and Neuropsychological Factors in Patients With Opioid Use Disorder on Methadone Maintenance Therapy

Objective: Abnormal selective attention to drug cues and negative affect is observed in patients with substance dependence, and it is closely associated with drug addiction and relapse. Methadone maintenance is an effective replacement therapy to treat heroin addiction, which significantly reduces the relapse rate. The present study examines whether the patients with opioid use disorder on chronic methadone maintenance therapy exhibit abnormal attentional bias to drug cues and negative-affective cues. Moreover, its relation to therapeutic and neuropsychological factors is also examined. Methods: Seventy-nine patients with opioid use disorder under chronic methadone maintenance therapy and 73 age-, sex-, and education-matched healthy controls were recruited and assessed for attentional bias to drug cues and negative affect using a dot-probe detection task. Correlational analysis was used to examine the relationships between the attentional bias and the demographic, therapeutic, and neuropsychological factors. Results: No significant overall patient-control group difference is observed in drug-related or negative-affective-related attentional bias scores. In the patient group, however, a significant negative correlation is found between the attentional bias scores to negative-affective cues and the duration of methadone treatment (p = 0.027), with the patients receiving longer methadone treatment showing less attentional avoidance to negative-affective cues. A significant positive correlation is found between the negative affect-induced bias and the impulsivity score (p = 0.006), with more impulsive patients showing higher attentional avoidance to negative affective cues than less impulsive patients. Additionally, the patients detect a smaller percentage of probe stimuli following the drug (p = 0.029) or negative-affective pictures (p = 0.009) than the healthy controls. Conclusion: The results of the present study indicate that the patients under chronic methadone maintenance therapy show normalized attentional bias to drug and negative-affective cues, confirming the involuntary attention of the patients is not abnormally captured by external drug or negative-affective clues. Our findings also highlight that the attentional avoidance of negative-affective cues is modulated by the duration of methadone treatment and the impulsivity level in the patients.