Adolescents exposed to trauma are more likely to engage in alcohol and marijuana use compared to their nontrauma‐exposed counterparts; however, little is known about factors that may moderate these associations. This study examined the potential moderating effect of cognitions relevant to exposure to trauma (i.e., negative view of self, world, and future) in the association between posttraumatic stress disorder (PTSD) diagnosis and substance use among a psychiatric inpatient sample of 188 adolescents. Findings were that PTSD diagnosis was not significantly associated with substance‐use diagnoses, but was associated with substance‐use symptoms, accounting for 2.9% and 9.6% of the variance in alcohol and marijuana symptoms, respectively. The association between PTSD diagnosis and substance use symptoms, however, was moderated by negative cognitions, with PTSD and high negative cognitions (but not low negative cognitions) being significantly positively associated with substance use symptoms. The relevant cognitions differed for alcohol symptoms and marijuana symptoms. Children and adolescents who experience trauma and PTSD may benefit from early interventions that focus on cognitive processes as one potential moderator in the development of posttrauma substance use. 標題：精神病院住院青少年中負面認知緩和PTSD和物質濫用間的關係 撮要：受創青少年比未受創者更多濫用酒精和大麻，但未知有何因素緩解當中關係。本文檢視188名精神科住院青少年，其中與創傷經歷有關的認知的潛在緩解作用在創傷後壓力症(PTSD)診斷和物質濫用兩者的關係。結果是PTSD診斷未與物質濫用診斷有明顯關係，但卻與物質濫用症狀相連(分別是2.9%和9.6%酒精和大麻症狀的變量) 。負面認知能緩和PTSD診斷及物質濫用症狀之間的關係，而PTSD和強烈負面認知(但非輕微負面認知)顯著地與物質濫用症狀呈正相連。酒精和大麻症狀的相應認知有異。兒童及青少年經歷創傷及PTSD後可受惠於聚焦認知過程的早期介入，以期緩解創傷後物質濫用的發生。 标题：精神病院住院青少年中负面认知缓和PTSD和物质滥用间的关系 撮要：受创青少年比未受创者更多滥用酒精和大麻，但未知有何因素缓解当中关系。本文检视188名精神科住院青少年，其中与创伤经历有关的认知的潜在缓解作用在创伤后压力症(PTSD)诊断和物质滥用两者的关系。结果是PTSD诊断未与物质滥用诊断有明显关系，但却与物质滥用症状相连(分别是2.9%和9.6%酒精和大麻症状的变量) 。负面认知能缓和PTSD诊断及物质滥用症状之间的关系，而PTSD和强烈负面认知(但非轻微负面认知)显著地与物质滥用症状呈正相连。酒精和大麻症状的相应认知有异。儿童及青少年经历创伤及PTSD后可受惠于聚焦认知过程的早期介入，以期缓解创伤后物质滥用的发生。