Time is of essence - Abnormal time perspectives mediate the impact of childhood trauma on depression severity

Background: Major depressive disorder (MDD) is a multifaceted mental disorder where participants, in addition to various symptoms, often suffer from increased focus on past time perspective and higher incidence of childhood trauma. Whether the abnormal time perspective is a result of the depressive symptoms or, alternatively, mediates between childhood trauma and depression remains unclear. Aims: To examine the triangular relationship between early life trauma, time perspective, and depressive symptoms. Method: We investigated a large-scale MDD sample (n = 93) and healthy subject sample (n = 69) with Beck depression inventory-II (BDI-II), Beck hopelessness scale (BHS), childhood traumatic questionnaire-Short Form (CTQ-SF), and the Zimbardo time perspective inventory (ZTPI). Results: The MDD patients reported more childhood trauma experiences, and were featured by abnormal time perspectives on past and future when compared to healthy control. By applying two alternative mediation models, we observed that the time perspective acted as a mediator between childhood trauma and depressive symptom severity, rather than as a consequence of depressive symptom. Furthermore, this abnormal time perspective was a risk factor to MDD, as the childhood trauma only mediated the time perspective in MDD. Finally, we showed that time perspective was a long-term personal trait and unchanged after the remission of depression symptoms under five-day transcranial magnetic stimulation. Conclusions: Abnormal time perspective mediates the impact of early childhood trauma on depressive symptomatology. Besides better understanding of the temporal basis of depressive symptoms, we highlight the importance of preventive time perspective therapy in subjects with childhood trauma.