Hierarchical psychopathology contributes to providing a broader picture of the links between emerging personality structures such as the DSM‐5/ICD‐11 trait models and clinical disorders. The present study aimed to predict the specific and general clinical symptoms by the less studied constructs of the ICD‐11 model (negative affectivity, detachment, dissociality, disinhibition, and anankastia). Data from 642 young adults from Iran (63% female, 18–34 years) were collected by three mental symptom scales and the Personality Inventory for DSM‐5 (PID‐5), which was recently used to harmonize the constructs of the DSM‐5 and ICD‐11 trait models. Multiple linear regressions showed that the ICD‐11 model significantly predicted both the specific clinical symptoms (ranging from R2 = 0.15 to 0.40) and the general factor of clinical symptoms extracted by exploratory factor analysis (R2 = 0.40, all p < 0.001). Negative affectivity was the strongest construct correlated with both the specific symptoms (ranging from β = 0.36 to 0.69) and the general symptom factor (β = 0.59, all p < 0.001). Because the ICD‐11 trait model is a practical structure related to the clinical psychopathology in young adults, screening for maladaptive traits can help clinicians in case formulation for diagnosis and treatment.