<p>This study investigates the associations between addiction severity, perceived parental bonding, obsessive-compulsive symptoms, and aggression in individuals undergoing inpatient treatment for alcohol or psychoactive substance dependence. Using a correlational survey design, data were collected from 165 participants at a detoxification center in Istanbul. The results showed that obsessive-compulsive symptoms were negatively correlated with both aggression (<i>r</i> = –.263, <i>p</i> &lt; .05) and addiction severity (<i>r</i> = –.229, <i>p</i> &lt; .05). A significant positive relationship was found between parental overprotection—particularly paternal—and obsessive-compulsive symptoms (<i>r</i> = .250, <i>p</i> &lt; .05). Multiple regression analyses revealed that addiction severity (β = 0.25, <i>p</i> &lt; .05) and lower paternal care (β = –0.20, <i>p</i> &lt; .05) significantly predicted higher aggression scores. Additionally, individuals with neglectful or affectionless-control paternal bonding types reported higher aggression levels compared to those with optimal bonding. These findings highlight the importance of early caregiving experiences and comorbid psychological traits in understanding addiction-related behavioral outcomes.</p>