The Revised Olweus Bully/Victim Questionnaire (OBVQ) is among the few bullying assessment instruments with well-established psychometric properties in different countries. Nevertheless, the psychometric properties of the Brazilian version (Questionário de Bullying de Olweus -QBO) have not been determined. We aimed at verifying the construct validity and reliability of the bully and victim scales of the QBO. To achieve that goal, the victim and bully scales were assessed using polytomous item response theory (IRT). The best fit was obtained with a generalized partial credit model that is capable of measuring the specific discriminating power for each item in these scales. The QBO was administered to 703 public school students (mean age: 13 years; standard deviation = 1.58). Based on IRT analysis, the number of response categories in each item was reduced from four to three. Cronbach reliability scores were satisfactory: α = 0.85 (victim scale) and α = 0.87 (bully scale). In this study, hurtful comments, persecution, or threats had high power to discriminate victims and bullies. For both QBO scales, higher severity parameters were observed for direct bullying items. The results also show that the construct of both QBO scales measures the same construct proposed for the overall instrument. Thus, the QBO can be administered to different Brazilian populations to assess the main characteristics of bullying: repetition of behavior over time and intentionally acting to humiliate, threaten, or harm somebody.

Recent reports suggest that brain-derived neurotrophic factor (BDNF) could be a biomarker for relapse, drug craving and withdrawal severity. In particular, elevated BDNF levels among former cocaine users have been associated with higher rates of relapse in 90 d. However, no data are available on BDNF levels at baseline and during crack cocaine withdrawal. This study evaluated BDNF among crack cocaine users during inpatient treatment, before and after withdrawal, vs. healthy controls. Clinical correlates with changes in BDNF levels were also assessed. Serum BDNF was evaluated in 49 male crack users on the first and last days of hospitalization and in 97 healthy controls. Serum BDNF was assayed using a sandwich ELISA kit. BDNF levels were significantly lower upon admission when compared to controls, even after adjustment for age, length of inpatient treatment, number of crack rocks used in the last 30 d, years of crack use and interaction between the latter two variables. At discharge, BDNF levels between patients and controls were similar. Number of crack rocks used in the last 30 d and years of crack use were inversely correlated with the outcome. Our findings show that BDNF levels increase during early crack cocaine withdrawal, at an inverse correlation with number of crack rocks used in the last 30 d and years of crack use.

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