Predictive factors associated with driving under the influence among Brazilian drug-using drivers.

The incidence of driving under the influence of psychoactive substances (DUI) and its recidivism can be curtailed by the proper identification of specific and predictive characteristics among drug users. In this sense, interpersonal violence (IV), psychiatric comorbidity and impulsivity seem to play an important role in DUI engagement according to previous studies. There are, however, limited data originated from low and middle income countries. In the present study, drug-using Brazilian drivers reporting DUI (n = 75) presented a higher prevalence of bipolar disorders (BD; DUI: 8% vs. non-DUI: 0%, p < 0.001), lower prevalence of obsessive-compulsive disorder (OCD; DUI: 0% vs. non-DUI: 12.6%, p < 0.001), and higher prevalence of childhood trauma (DUI: 65.3% vs. non-DUI: 46.8%, p = 0.022) than those not reporting DUI (n = 79). The evaluation of impulsivity though the Barratt Impulsivity Scale, which give impulsivity scores ranging from 30 to 120, showed higher impulsivity scores in the DUI group (80.4 ± 8) than in the non-DUI group (77.2 ± 10, p = 0.045). In general, subjects were young adults (mean age of 36 ± 9 years), Caucasians (58.4%), not married (61.0%), and with elementary schooling (40.3%) with no significant differences in demographic characteristics between drivers with and without DUI behavior. A multiple Poisson regression model showed that individuals reporting IV as perpetrators and history of childhood trauma were more likely to report DUI (PR: 1.66, 95%CI 1.22-2.7; PR: 1.57, 95%CI 1.02-2.42, respectively). The overlapping of violent situations (childhood trauma, IV and DUI) in some individuals presented here corroborates literature data suggesting that DUI can be an externalizing expression of a range of risky behavior, such as impulsiveness and aggressiveness. Moreover, while BD and higher impulsivity scores seem to act as risk factors for DUI, OCD was shown as a protective factor. These results corroborate the hypothesis that individuals with high risk for DUI could probably be identified by multidimensional assessment of cognitive, risky taking, and personality traits, which perhaps could facilitate the development of focused interventions.

Accumbens volumes are reduced among crack-cocaine users.

The brain reward system is known to be the neuroanatomical basis of addictive behaviors. Systemic, cognitive and functional consequences of crack-cocaine addiction are clinically evident, but the neuroanatomical underpinnigs are not yet well understood. We aim to assess the neuroanatomical differences between crack-cocaine patients and paired healthy controls. Fifteen crack-cocaine patients recently discharged from the Addiction Unit of the Hospital de Clínicas de Porto Alegre and fifteen controls matched for gender, age, education and handedness were scanned using a Philips Achieva 1.5T MRI equipment. All subjects had negative positive tests at admission and patients had at least 15days of detoxification. Active neurologic, inflammatory, cardiovascular or systemic comorbidities were excluded. Subcortical structure volumes were determined using Freesurfer v5.1. Controls had greater volumes in the left accumbens (t=3.604, df=28, p=0.001) compared to patients. Right accumbens volumes were also greater in controls (t=2.098, df=28, p=0.045). Groups did not differ regarding intracranial volumes (p=0.514). This preliminary and innovative data on crack-cocaine dependence suggests that there is a volumetric reduction of the accumbens, a region that has a significant role in motivation, pleasure, reward and reinforcement learning, and it could play a central role in the pathophysiology of this drug addiction. Therefore, these findings may contribute to understand some behavioral and cognitive deficits in this population.