Experiencing severe stress in childhood, such as abuse or losing a parent, has long been known to predispose a person to a number of unhealthy behaviors in adulthood. In a paper published in the journal Hippocampus, Tara Patterson and colleagues in the Knowlton lab in ICLM show that people who had experienced severe childhood stress may have a greater tendency to develop habits. This is important because it could explain why they are more likely to become addicted to drugs, get hooked on cigarettes, or compulsively overeat. The researchers speculate that childhood stress may alter the balance between brain systems important for goal-directed actions and habits. Behaviors such as experimenting with drugs, drinking, or even eating unhealthy food, become severe health problems when they become habitual, and habits are notoriously hard to break. If habits are formed too readily in people who had experienced childhood stress, it may be one reason they are at greater risk to develop addictions. These findings suggest interventions to help people who are at risk; for example: for these people it may be especially critical to develop healthy habits (e.g. an exercise routine) to replace unhealthy ones.