This study determined whether the climate of increased anxiety following the terrorist attacks of September 11, 2001, and the subsequent anthrax cases, led to increased anxiety-related physician visits. A retrospective, population-based study of all Ontario residents was conducted to identify physician visits using Ontario's universal health care insurance program. Interventional autoregressive integrated moving average (ARIMA) time series models were used to examine the impact of the terrorist attacks and anthrax infections on the rate of anxiety-related physician visits. Neither the terrorist attacks of September 11 (P > or = 0.40) nor the anthrax infections in October and November (P > or = 0.14) had a statistically significant impact on the rate of anxiety-related visits to physicians. As such, the climate of heightened anxiety did not result in increased demand for mental health services.