Early childhood trauma refers to various types of adversity and traumatic events experienced during the early years of a person's life. This is deemed the most critical developmental period in human life by psychologists. A critical period refers to a sensitive time during the early years of childhood in which children may be more vulnerable to be affected by environmental stimulation. These traumatic events can include serious sickness, natural disasters, family violence, sudden separation from a family member, being the victim of abuse, or suffering the loss of a loved one. Traumatic experiences in early childhood can result in severe consequences throughout adulthood, for instance developing post-traumatic stress disorder, depression, or anxiety. Negative childhood experiences can have a tremendous impact on future violence victimization and perpetration, and lifelong health and opportunity. However, not all children who are exposed to negative stimuli in early childhood will be affected severely in later life; some children come out unscathed after being faced with traumatic events, which is known as resilience. Many factors can account for the invulnerability displayed by certain children in response to adverse social conditions: gender, vulnerability, social support systems, and innate character traits. Much of the research in this area has referred to the Adverse Childhood Experiences Study (ACE) study. The ACE study found several protective factors against developing mental health disorders, including mother-child relations, parental health, and community support. However, having adverse childhood experiences creates long-lasting impacts on psychosocial functioning, such as a heightened awareness of environmental threats, feelings of loneliness, and cognitive deficits. Individuals with ACEs are more prone to developing severe symptoms than individuals in the same diagnostic category. Emotional Functioning Research shows that even witnessing traumatic events can impact the physical development of a child’s brain — potentially leading to lifelong impairments in emotional functioning. In particular, they could diminish the structure and functioning of brain systems. Some children may forget the traumatic event all together, thought it can re-surface years later with severe symptoms or not surface at all. Moreover, youth that grow up in emotionally dysfunctional environments typically don't have the opportunity to appropriately feel and express emotions, which can cause further distress accompanied by severe symptoms that persist into adulthood. This can further cause a person difficulty in creating or maintaining relationships, or further frustration and anxiety. Similarly, internalizing problems such as anxiety, depression, withdrawal, and somatic complaints are related to other forms