Dual diagnosis, defined as the co-occurrence of a mental disorder and a substance use disorder, is frequently associated with increased clinical severity, functional impairment, and poorer health outcomes. Identifying psychosocial protective factors related to better clinical and functional outcomes is essential to improve patient care and treatment planning.

The aim of this observational, cross-sectional, single-center study is to analyze psychosocial protective factors and their association with clinical-functional outcomes in hospitalized patients with dual diagnosis. The study will be conducted in a general hospital setting and will include adult inpatients diagnosed with dual diagnosis according to clinical criteria.

Sociodemographic, clinical, and psychosocial variables will be collected using standardized assessment tools and clinical records. The results of this study are expected to contribute to a better understanding of psychosocial factors associated with clinical severity and functional outcomes in patients with dual diagnosis, supporting more comprehensive and patient-centered care approaches.

Dual diagnosis, characterized by the coexistence of a mental disorder and a substance use disorder, represents a major clinical challenge in mental health services. Patients with dual diagnosis frequently present greater clinical complexity, higher rates of hospitalization, functional impairment, and difficulties in treatment adherence. Beyond clinical variables, psychosocial factors may play a relevant role as protective elements influencing clinical and functional outcomes.

This study is designed as an observational, cross-sectional, single-center study conducted in a general hospital. The study population will consist of adult patients hospitalized with a clinical diagnosis of dual diagnosis. Participants will be recruited during their hospital admission according to predefined inclusion and exclusion criteria.

Data collection will include sociodemographic information, clinical variables related to psychiatric and substance use disorders, and psychosocial factors considered potentially protective. Clinical-functional outcomes will be assessed using standardized instruments and information obtained from medical records. All data will be collected as part of routine clinical assessment, without introducing any experimental intervention.

The primary objective of the study is to evaluate the association between psychosocial protective factors and clinical-functional outcomes in hospitalized patients with dual diagnosis. Secondary objectives include describing the sociodemographic and clinical characteristics of the study population and exploring the relationship between psychosocial variables and indicators of clinical severity.

This study does not involve the administration of investigational drugs or devices and does not modify standard clinical practice. The research protocol has been reviewed and approved by the corresponding Ethics Committee. The findings are expected to provide relevant information to support a biopsychosocial approach in the assessment and management of patients with dual diagnosis.

Inclusion Criteria:

• Adults (≥18 years).
• Hospitalized patients with a clinical diagnosis of dual diagnosis.
• Ability to provide informed consent.

Exclusion Criteria:

• Severe cognitive impairment or acute clinical condition preventing assessment.
• Refusal or inability to provide informed consent.

Adult inpatients hospitalized in a general hospital with a clinical diagnosis of dual diagnosis.

Individual participant data will not be shared to protect participant confidentiality and in accordance with local ethics committee approval and institutional data protection regulations.