A worker filed a claim for mental stress he said was caused by a series of some 15 workplace incidents that took place over three to four years. His claim was denied. The Appeals Commission upheld the denial. The worker had serious psychiatric problems before any of these incidents happened. And these events didn’t aggravate his pre-existing mental condition to the point that he could no longer do his job. Thus, the worker didn’t have a compensable claim for mental stress [Decision No: 2012-683,  CanLII 43145 (AB WCAC), July 27, 2012].