Incidence and Associated Risk Factors of Traumatic Brain Injury in a Cohort of Homeless and Vulnerably Housed Adults in 3 Canadian Cities :

The high rate of co-occurrence of substance use disorders and other psychiatric disorders is well established. The population of people with co-occurring disorders is heterogeneous, and the prevalence of comorbidity differs by diagnostic group. One of the overarching issues in the area of comorbidity is the nature of the connection between psychiatric disorders and substance use disorders. The rapid development of technical advances in the neurosciences has led to a better understanding of the molecular biology, neurotransmitter systems, and neural circuitry involved in mental illness and substance use disorders. The authors discuss the neurobiological interface between substance use disorders and other psychiatric disorders with an emphasis on emerging data concerning four psychiatric disorders that commonly co-occur with substance use disorders: depression/mood disorders, posttraumatic stress disorder, attention deficit hyperactivity disorder, and schizophrenia. Better understanding of the connection between substance use disorders and psychiatric disorders could have a profound effect on prevention and treatment.

To determine the association of report of any history of head injury with loss of consciousness or confusion and a lifetime diagnosis of psychiatric disorder in a general population. A probability sample of adults from the New Haven portion of the NIMH Epidemiologic Catchment Area programme were administered standardized and validated structured interviews. The main outcome measures were lifetime prevalence of psychiatric disorders and suicide attempt in individuals with and without a history of traumatic brain injury. Among 5034 individuals interviewed, 361 admitted to a history of severe brain trauma with loss of consciousness or confusion (weighted rate of 8.5/100). When controlling for sociodemographic factors, quality of life indicators and alcohol use, risk was increased for major depression, dysthymia, panic disorder, OCD, phobic disorder and drug abuse/dependence. In addition, lifetime risk of suicide attempt was greater in those who had suffered head injury. Individuals with a history of traumatic brain injury have significantly higher occurrence for psychiatric disorders and suicide attempts in comparison with those without head injury and have a poorer quality of life. Future studies should examine the nature of this relationship, focusing on the severity of the brain injury and the temporal contiguity of the brain injury and psychiatric disorder.