How symptoms of prolonged grief disorder, posttraumatic stress disorder, and depression relate to each other for grieving ICU families during the first two years of bereavement

BACKGROUND: Bereaved ICU family surrogates are at risk of comorbid prolonged grief disorder (PGD), posttraumatic stress disorder (PTSD), and depression. Knowledge about temporal relationships between PGD, PTSD, and depression is limited by a lack of relevant studies and diverse or inappropriate assessment time frames given the duration criterion for PGD. We aimed to determine the temporal reciprocal relationships between PGD, PTSD, and depressive symptoms among ICU decedents’ family surrogates during their first 2 bereavement years with an assessment time frame reflecting the PGD duration criterion. METHODS: This prospective, longitudinal, observational study examined PGD, PTSD, and depressive symptoms among 303 family surrogates of ICU decedents from two academic hospitals using 11 items of the Prolonged Grief Disorder-13, the Impact of Event Scale—Revised, and the depression subscale of the Hospital Anxiety and Depression Scale, respectively, at 6, 13, 18, and 24 months post-loss. Cross-lagged panel modeling was conducted: autoregressive coefficients indicate variable stability, and cross-lagged coefficients indicate the strength of reciprocal relationships among variables between time points. RESULTS: Symptoms (autoregressive coefficients) of PGD (0.570–0.673), PTSD (0.375–0.687), and depression (0.591–0.655) were stable over time. Cross-lagged standardized coefficients showed that depressive symptoms measured at 6 months post-loss predicted subsequent symptoms of PGD (0.146) and PTSD (0.208) at 13 months post-loss. PGD symptoms did not predict depressive symptoms. PTSD symptoms predicted subsequent depressive symptoms in the second bereavement year (0.175–0.278). PGD symptoms consistently predicted subsequent PTSD symptoms in the first 2 bereavement years (0.180–0.263), whereas PTSD symptoms predicted subsequent PGD symptoms in the second bereavement year only (0.190–0.214). PGD and PTSD symptoms are bidirectionally related in the second bereavement year. CONCLUSIONS: PGD, PTSD, and depressive symptoms can persist for 2 bereavement years. Higher PGD symptoms at 6 months post-loss contributed to the exacerbation of PTSD symptoms over time, whereas long-lasting PTSD symptoms were associated with prolonged depression and PGD symptoms beyond the first bereavement year. Identification and alleviation of depression and PGD symptoms as early as 6 months post-loss enables bereaved surrogates to grieve effectively and avoid the evolution of those symptoms into long-lasting PGD, PTSD, and depression. SUPPLEMENTARY INFORMATION: The online version contains supplementary material available at 10.1186/s13054-022-04216-5.