Drug use among medical students in São Paulo, Brazil: a cross-sectional study during the coronavirus disease 2019 pandemic

ABSTRACT BACKGROUND: Medical students demonstrate higher rates of substance use than other university students and the general population. The challenges imposed by the coronavirus disease 2019 (COVID-19) pandemic raised significant concerns about mental health and substance use. OBJECTIVES: Assess the current prevalence of substance use among medical students at the University of São Paulo and evaluate the impact of the COVID-19 pandemic on drug consumption. DESIGN AND SETTING: A cross-sectional study was conducted on 275 medical students from the University of São Paulo Medical School (São Paulo, Brazil) in August 2020. METHODS: Substance use (lifetime, previous 12 months, and frequency of use before and during the COVID-19 pandemic) and socioeconomic data were assessed using an online self-administered questionnaire. Symptoms of depression were assessed using the Patient Health Questionnaire-9. RESULTS: Alcohol was the most consumed substance in their lifetime (95.6%), followed by illicit drugs (61.1%), marijuana (60%), and tobacco (57.5%). The most commonly consumed substances in the previous year were alcohol (82.9%), illicit drugs (44.7%), marijuana (42.5%), and tobacco (36%). Students in the first two academic years consumed fewer substances than those from higher years. There was a decreasing trend in the prevalence of most substances used after the COVID-19 pandemic among sporadic users. However, frequent users maintained their drug use patterns. CONCLUSION: The prevalence of substance use was high in this population and increased from the basic to the clinical cycle. The COVID-19 pandemic may have affected the frequency of drug use and prevalence estimates.

An electric field modeling study with meta-analysis to understand the antidepressant effects of transcranial direct current stimulation (tDCS)

Objective: Transcranial direct current stimulation (tDCS) has mixed effects for major depressive disorder (MDD) symptoms, partially owing to large inter-experimental variability in tDCS protocols and their correlated induced electric fields (E-fields). We investigated whether the E-field strength of distinct tDCS parameters was associated with antidepressant effect. Methods: A meta-analysis was performed with placebo-controlled clinical trials of tDCS enrolling MDD patients. PubMed, EMBASE, and Web of Science were searched from inception to March 10, 2023. Effect sizes of tDCS protocols were correlated with E-field simulations (SimNIBS) of brain regions of interest (bilateral dorsolateral prefrontal cortex [DLPFC] and bilateral subgenual anterior cingulate cortex [sgACC]). Moderators of tDCS responses were also investigated. Results: A total of 20 studies were included (21 datasets, 1,008 patients), using 11 distinct tDCS protocols. Results revealed a moderate effect for MDD (g = 0.41, 95%CI 0.18-0.64), while cathode position and treatment strategy were found to be moderators of response. A negative association between effect size and tDCS-induced E-field magnitude was seen, with stronger E-fields in the right frontal and medial parts of the DLPFC (targeted by the cathode) leading to smaller effects. No association was found for the left DLPFC and the bilateral sgACC. An optimized tDCS protocol is proposed. Conclusions: Our results highlight the need for a standardized tDCS protocol in MDD clinical trials. Registration number: PROSPERO CRD42022296246.

Distractibility, anxiety, irritability, and agitation symptoms are associated with the severity of depressive and manic symptoms in mixed depression

Objective: To explore whether there is an association between distractibility, anxiety, irritability, and agitation (DAIA) symptoms and the severity of depressive and manic symptoms. Methods: Patients with unipolar and bipolar disorder (I and II) and mixed depression were evaluated. DAIA symptoms were assessed using previously described definitions. Results: The full analysis set comprised 100 patients. The severity of depressive symptoms in mixed depression, assessed by Montgomery-Åsberg Depression Rating Scale (MADRS), was significantly associated with the presence of two or more DAIA symptoms in the bipolar sample, influenced mainly by anxiety. The severity of manic symptoms in mixed depression, assessed by Young Mania Rating Scale (YMRS), was significantly associated with the presence of two or more DAIA symptoms in the bipolar sample and three or four DAIA symptoms in the unipolar sample. Conclusion: DAIA symptoms were associated with greater severity of manic symptoms in mixed depression. DAIA symptoms must be evaluated in all patients with mixed features and are associated with the severity of depressive and manic symptoms in mixed depression. Clinical trial registration: ClinicalTrials.gov (NCT04123301).

Non-invasive brain stimulation therapies / Terapias de neuroestimulação não invasivas

Noninvasive brain stimulation therapies are a promising field for the development of new protocols for the treatment of neuropsychiatric disorders. They are based on the stimulation of neural networks with the intent of modeling their synaptic activity to adequate levels. For this, it is necessary to precisely determine which networks are related to which brain functions, and the normal activation level of each of these networks, so that it is possible to direct the stimulation to the affected networks in order to induce the desired effects. These relationships are under intense investigation by the scientific community, and will contribute to the advancement of treatments by neurostimulation, with the emergence of increasingly accurate and effective protocols for different disorders. Currently, the most used techniques are Transcranial Direct Current Stimulation and Transcranial Magnetic Stimulation, with the most common applications being for treating Major Depressive Disorder. The advancement of research in this field may determine new target networks for stimulation in the treatment of other disorders, extending the application of these techniques and also our knowledge about brain functioning.

As terapias biológicas não invasivas se apresentam como um campo promissor para o desenvolvimento de novos protocolos de tratamento de transtornos neuropsiquiátricos. Elas se baseiam na estimulação de redes neurais com intuito de modular sua atividade sináptica para níveis adequados. Para isso, é necessário a determinação precisa de quais redes estão relacionadas a quais funções cerebrais, e do nível de ativação normal de cada uma dessas redes, para que então seja possível direcionar a estimulação às redes afetadas a fim de induzir os efeitos desejados. Essas relações estão sob intensa investigação pela comunidade científica, e vão contribuir para o avanço dos tratamentos por neuroestimulação, com o surgimento de protocolos cada vez mais precisos e efetivos para diferentes transtornos. Atualmente, as técnicas mais utilizadas são a Estimulação Transcraniana por Corrente Contínua e a Estimulação Magnética Transcraniana, sendo a aplicação mais comum no tratamento do Transtorno Depressivo Maior. O avanço das pesquisas possivelmente determinará novas redes alvo para estimulação no tratamento de outros transtornos, estendendo a aplicação dessas técnicas e também do nosso conhecimento sobre o funcionamento cerebral.