Cingulate cortical thickness in cocaine use disorder: mediation effect between early life stress and cocaine consumption.

OBJECTIVE: The cingulate gyrus is implicated in the neurobiology of addiction, such as chronic cocaine consumption. Early life stress (ELS) is an important moderator of cocaine use disorder (CUD). Therefore, we investigated the effect of CUD on cingulate cortical thickness and tested whether a history of ELS could influence the effects of CUD. METHODS: Participants aged 18-50 years (78 with CUD due to crack cocaine consumption and 53 healthy controls) underwent magnetic resonance imaging and the cingulate thickness (rostral anterior, caudal anterior, posterior, and isthmus regions) was analysed. The clinical assessment comprised the Childhood Trauma Questionnaire (CTQ) and the Addiction Severity Index. Group comparisons adjusting by sex, age, and education were performed. Mediation models were generated where lifetime cocaine use, CTQ score, and cortical thickness corresponded to the independent variable, intermediary variable, and outcome, respectively. RESULTS: Group comparisons revealed significant differences in six out of eight cingulate cortices, showing lower thickness in the CUD group. Furthermore, years of regular cocaine use was the variable most associated with cingulate thickness. Negative correlations were found between CTQ scores and the isthmus cingulate (right hemisphere), as well as with the rostral anterior cingulate (left hemisphere). In the mediation analysis, we observed a significant negative direct effect of lifetime cocaine use on the isthmus cingulate and an indirect effect of cocaine use mediated by CTQ score. CONCLUSION: Our findings suggest that a history of ELS could aggravate the negative effects of chronic cocaine use on the cingulate gyrus, particularly in the right isthmus cingulate cortex.

Cortical thickness and subcortical volume abnormalities in male crack-cocaine users.

Crack-cocaine offers a higher risk of abuse than intranasal and intravenous use of cocaine. Yet, current treatments remain disappointing and our understanding of the mechanism of crack-cocaine neurotoxicity is still incomplete. Magnetic resonance images studies on brain changes of crack-cocaine addicts show divergent data. The present study investigated gray matter (GM) abnormalities in crack-cocaine dependents (n = 18) compared to healthy controls (n = 17). MRI data was analysed using FreeSurfer and voxel-based morphometry (VBM). FreeSurfer analysis showed that CD had decreased cortical thickness (CT) in the left inferior temporal cortex (lTC), left orbitofrontal cortex (lOFC) and left rostro frontal cortex (lRFC), enlargement in left inferior lateral ventricle, and smaller GM volume in right hippocampus and right ventral diencephalon. VBM analysis showed that CD had significantly decreased GM volume in left Putamen and left nucleus accumbens. Furthermore, we found a negative correlation between duration of crack-cocaine use and lTC CT. These results provide compelling evidence for GM abnormalities in CD and also suggest that duration of crack-cocaine use may be associated with CT alterations.

Patterns of non-medical use of methylphenidate among 5th and 6th year students in a medical school in southern Brazil / Padrões do uso não médico de metilfenidato em estudantes do 5º e do 6º ano de uma faculdade de medicina do Brasil

Objectives: To evaluate the prevalence of methylphenidate (MPH) use among 5th and 6th year medical students, to discriminate MPH use with and without medical indication, and to correlate MPH use with alcohol intake. Methods: This is a cross-sectional study in which medical students were invited to answer a questionnaire to evaluate academic and socioeconomic status, MPH use patterns, and attitudes towards neuroenhancing drugs. The Alcohol Use Disorders Identification Test (AUDIT) was used to assess alcohol intake; a score ≥ 8 suggests potentially hazardous alcohol use. Results: Fifty-two participants (34.2%) had already used MPH, of which 35 (23.02%) had used it without medical indication. The number of 6th year students who had used MPH was more than twice higher than that of their 5th year counterparts (32.89 vs. 13.15%, respectively; p = 0.004). Also, 43.6% (p = 0.031) of the users of MPH had an AUDIT score ≥ 8; 33.3% (p = 0.029) of non-medical users of MPH had an AUDIT score ≥ 8. Conclusions: In this study, the use of MPH without medical indication was prevalent. Our findings also confirmed the association between non-medical use of MPH and potentially hazardous alcohol use (AU)

Objetivos: Avaliar a prevalência do uso do metilfenidato entre estudantes do 5º e do 6º ano de uma faculdade de medicina, discriminar o uso com ou sem indicação médica e correlacionar o uso de metilfenidato com a ingestão de álcool. Métodos: Este é um estudo transversal, em que os alunos de medicina foram convidados a responder um questionário para avaliação do status socioeconômico e acadêmico, padrões do uso do metilfenidato e atitude em relação a drogas potencializadoras da cognição. Também foi aplicado o questionário The Alcohol Use Disorder Identification Test (AUDIT), que avalia o consumo de bebidas alcoólicas, onde um score ≥ 8 significa ingestão potencialmente perigosa de álcool. Resultados: Cinquenta e dois participantes (34,2%) já haviam usado metilfenidato, sendo que 35 destes (23,02%) haviam usado a substância sem indicação médica. O número de estudantes do 6º ano que fizeram uso não médico de metilfenidato foi mais de duas vezes maior do que o número de estudantes do 5º ano (32,89 versus 13,15%, respectivamente; p = 0,004). Em relação ao AUDIT, 43,6% (p = 0,031) dos usuários de metilfenidato tiveram escores ≥ 8; 33,3% (p = 0,029) dos usuários não médicos de metilfenidato tiveram escores ≥ 8 no AUDIT. Conclusões: Neste estudo, o uso de metilfenidato sem indicação médica foi prevalente. Os achados também evidenciaram a associação entre o uso não médico de metilfenidato e o uso potencialmente perigoso de álcool (AU)

Patterns of non-medical use of methylphenidate among 5th and 6th year students in a medical school in southern Brazil.

OBJECTIVES: To evaluate the prevalence of methylphenidate (MPH) use among 5th and 6th year medical students, to discriminate MPH use with and without medical indication, and to correlate MPH use with alcohol intake. METHODS: This is a cross-sectional study in which medical students were invited to answer a questionnaire to evaluate academic and socioeconomic status, MPH use patterns, and attitudes towards neuroenhancing drugs. The Alcohol Use Disorders Identification Test (AUDIT) was used to assess alcohol intake; a score ≥ 8 suggests potentially hazardous alcohol use. RESULTS: Fifty-two participants (34.2%) had already used MPH, of which 35 (23.02%) had used it without medical indication. The number of 6th year students who had used MPH was more than twice higher than that of their 5th year counterparts (32.89 vs. 13.15%, respectively; p = 0.004). Also, 43.6% (p = 0.031) of the users of MPH had an AUDIT score ≥ 8; 33.3% (p = 0.029) of non-medical users of MPH had an AUDIT score ≥ 8. CONCLUSIONS: In this study, the use of MPH without medical indication was prevalent. Our findings also confirmed the association between non-medical use of MPH and potentially hazardous alcohol use.