Grant: Doctoral Award - Frederick Banting and Charles Best Canada Graduate Scholarships

Major Depressive Disorder (MDD) is a recurrent and impairing condition that affects approximately 1.25 million Canadians each year. Because of this, research aimed at understanding factors that cause and maintain depression is extremely important. Stress is a potent risk factor that has been implicated in the onset of MDD. Further, the role stress plays in triggering depression changes over the course of the disorder. The stress sensitization hypothesis suggests that severe stressors (e.g., spouse dies from cancer) are important for triggering the first episode; however, as the disorder progresses, minor stressors (e.g., argument with a friend) become more capable of eliciting a recurrence. Additionally, it has been demonstrated that a history of childhood maltreatment increases vulnerability to stress even prior to the very first depressive episode. The proposed study will examine the relation of maltreatment to stress sensitization in a way that will potentially impact the ability to recognize individuals vulnerable to stress and depression, and inform prevention, early intervention, and treatment planning. Specifically, this study will investigate whether the role of maltreatment in stress sensitization is dependent on several factors. These factors include depression history (first onset vs. recurrent), age (adolescence vs. adulthood), and specific characteristics of maltreatment including the type (physical vs. sexual vs. emotional abuse) and timing (maltreatment perpetrated in childhood vs. adolescence). Results from these objectives will help clarify the role of maltreatment in the initial etiology and ongoing pathology of depression across different developmental periods. This knowledge will help inform more effective treatments that target distal and proximal risk factors most strongly implicated in MDD. Further, it will help guide clinicians in allocating treatment resources to those most vulnerable to depression in the face of stress.