The presence and impact of traumatic brain injury among clients in treatment for co-occurring mental illness and substance abuse

Objectives: To compare diagnostic and treatment-related differences between persons participating in treatment for dually diagnosed substance use disorders and severe mental illness who have or do not have a history of traumatic brain injury (TBI).

Design: Prospective cohort.

Interventions: Not applicable.

Primary measures: Demographic information, diagnostic data, pre-treatment status, treatment participation and staff assessment of functioning.

Results: Seventy-two percent of participants in treatment for dually diagnosed substance use disorders and severe mental illness reported a history of at least one TBI. Participants with TBI had greater morbidity as reflected in more complex psychiatric diagnoses and greater likelihood of being diagnosed with an Axis II personality disorder. Participants with a TBI showed tendencies toward earlier onset of substance use and worse current functioning. Both a greater number of injuries and earlier age at first TBI showed some indications of being associated with worse morbidity.

Conclusions: Individuals dually diagnosed with substance use disorders and severe mental illness may have a high rate of TBI, which in turn could contribute to important clinical and treatment differences. Results also suggested the need for validated methods of identifying aspects of a prior history of TBI that provide more information than presence/absence.