Background: There is widespread agreement that traumatic experiences in early life play a crucial role in setting the stage for adult depression. Aim and objectives: This paper aimed to examine the evidence linking childhood abuse to the development of adult-onset depression. Methods: For the purpose of quantitatively comparing the magnitude of effect across exposure age groups, we scoured scholarly papers and databases including PubMed, Google Scholar, and Science Direct for information on the correlation among both Maltreatment exposure age and Depression. Studies conducted in English were sourced from electronic databases and grey literature up to April 6th, 2022. Included studies had to provide both: Data on when the abuse occurred and quantitative measures of the correlation between abuse in childhood and adult depression. Conclusion: Adults with a record of childhood abuse have a greater likelihood to have depressive disorders with a more severe clinical presentation during their adulthood than adults without. Exposure to severe, early-onset, chronic, and treatment-resistant depression throughout childhood is associated with a history of maltreatment, particularly physical neglect and emotional abuse. Clinical implications include a need for a thorough evaluation of emotional abuse, sexual abuse, and cumulative exposure to trauma in patients with chronic depression.