This study aimed to examine the same-sex matching effect of posttraumatic stress disorder (PTSD) symptoms from parents to children and the mediating role of children' sense of security and catastrophization. Longitudinal data from 447 parent-child dyads were acquired using self-report scales. Parents (77.0% mothers; Mage = 40.15 years old) reported their PTSD symptoms 3 months after Super Typhoon Lekima, and children (55.9% girls; Mage = 13.40 years old) reported their PTSD symptoms, sense of security, and catastrophization 3 months and 15 months after the typhoon. Results showed that intrusion in mothers predicated intrusion, avoidance, and hyperarousal symptoms in daughters, while avoidance and hyperarousal in mothers predicted the same symptoms in daughters. This was not observed in any other parent-child dyads. Moreover, mothers' intrusion positively predicted daughters' PTSD symptoms via daughters' sense of security and then catastrophization, while mothers' hyperarousal showed the opposite prediction. These findings suggest that a same-sex matching effect occurs from mothers to daughters in terms of intrusion, avoidance, and hyperarousal symptoms of PTSD. Thus, clinical interventions that target daughters' PTSD symptoms should also consider mothers' intrusion and avoidance symptoms. Moreover, it may be possible to develop interventions to improve daughters' sense of security.
Keywords: PTSD symptoms; mediating effect; parent–child dyads; same-sex matching effect.