Objectives: To characterize psychotropic medication use before and after traumatic brain injury (TBI) hospitalization among older adults. A secondary objective is to determine how receipt of indicated pharmacologic treatment for anxiety and post-traumatic stress disorder (PTSD) differs following TBI. Design: Retrospective cohort. Setting: United States. Participants: Medicare beneficiaries aged >= 65 years hospitalized with TBI between 2006 and 2010 with continuous drug coverage for 12 months before and after TBI (N = 60,276). Measurements: We obtained monthly psychotropic medication use by drug class and specific drugs from Medicare Part D drug event files. ICD-9 codes were used to define anxiety (300.0x) and PTSD (309.81). Results: Average monthly prevalence of psychotropic medication use among all patients hospitalized for TBI was 44.8%; antidepressants constituted 73%. Prevalence of psychotropic medication use increased from 2006 to 2010. Following TBI, psychotropic medication use increased slightly (OR: 1.05; 95% CI: 1.03, 1.06.) Tricyclic antidepressant use decreased post-TBI (OR: 0.76; 95% CI: 0.73, 0.79) whereas use of the sedating antidepressants mirtazapine (OR: 1.31; 95% CI: 1.25, 1.37) and trazadone (OR: 1.11; 95% CI: 1.06, 1.17) increased. Antipsychotic (OR: 1.15; 95% CI: 1.12, 1.19) use also increased post-TBI. Beneficiaries newly diagnosed with anxiety (OR: 0.42; 95% CI: 0.36, 0.48) and/or PTSD (OR: 0.39; 95% CI: 0.18, 0.84) post-TBI were less likely to receive indicated pharmacologic treatment. Conclusions: Older adults hospitalized with TBI have a high prevalence of psychotropic medication use yet are less likely to receive indicated pharmacological treatment for newly diagnosed anxiety and PTSD following TBI.