Prior studies have identified that individuals with comorbid substance use disorder and mental health disorder are at a greater risk of benzodiazepine abuse compared to individuals that present with mental health disorder without an accompanying substance use disorder. These studies were conducted in predominantly white populations, and little is known if the same associations are seen in safety net health care networks. Also, the literature is mixed as to whether or not psychiatrists’ prescription of benzodiazepines places individuals at undue risk of benzodiazepine abuse.

We use 2013–2015 electronic health record data from a Boston healthcare system. Patients with benzodiazapene abuse were identified if they had received treatment under the ICD-9 code 304.1. Benzodiazepine abuse was compared between patients with only mental illness and patients with existing comorbid substance and mental health disorder, in unadjusted comparisons and adjusted regression models. Covariates in regression models were used to identify subgroups at higher risk of benzodiazepine abuse.

Individuals with benzodiazepine abuse had higher rates of emergency room and inpatient use than patients with other mental health and/or substance use disorders. Those with comorbid substance and mental disorder were significantly more likely than individuals with mental or substance use disorder alone to abuse benzodiazepines (P < .01). Among those with benzodiazepine abuse, 93.3% were diagnosed with a mental illness, 75.6% were diagnosed with a substance use disorder (other than benzodiazepine), and 64.4% had comorbid anxiety disorder and substance use disorder. These analyses suggest that patients with benzodiazepine abuse have complex presentations and intensive service use.