Texas High Court Upholds Exclusion of Physician's Testimony that Cocaine and Alcohol Dependency Caused Defendants' Violent Conduct

A trial court did not abuse its discretion when it permitted a physician to testify that cocaine and alcohol dependency are associated with violent activity, but not that the defendant's dependency caused his particular violent conduct, the Texas Court of Criminal Appeals has ruled. From the opinion:

Dr. McQueen did have training as a researcher with regard to the treatment of addictions, and that training appears to have included knowledge of the interaction between cocaine and alcohol in the body and studies showing a correlation between cocaine and alcohol usage and violence. Under this record, however, the trial court could reasonably conclude that the pharmacological knowledge and studies were not a sufficient basis from which to draw a scientific conclusion about how any particular individual would behave. Of course, one might draw a layman's conclusion from evidence of a correlation between drug dependence and violence that a particular drug user's violence resulted from dependence, but that sort of conclusion is one that a jury is well-suited to make on its own, without the assistance of an expert.

See Roberts v. State, No. AP-75,051 (Tex. Crim. App. Apr. 18, 2007).