Statistical analysis
Data were analyzed using PASW Statistics 17.0.
Variables were analyzed descriptively, and results were
distributed in frequency tables. Data that could not be
retrieved were classified as lost and excluded from the
analysis. We controlled data for age, sex, demographic
characteristics and diagnosis, and a chi-square test and
the Fisher exact test were used to compare differences
between groups.
The sample was first divided into aggressive and
non-aggressive individuals. Aggressive individuals
were then separated into hostile (verbally aggressive
and aggressive against objects) and violent (physically
aggressive). After that, aggressive individuals were
divided into those that were aggressive against others
only (hetero-aggressive), and those that were also
aggressive towards themselves (self-aggressive). The
groups were compared using the Mann-Whitney U test.
The level of significance was set at 5% (α = 0.05).
The prevalence of aggression was described with 95%
confidence intervals (95%CI).