Mental disorders surpassed respiratory problems and all other ailments as the leading cause of hospitalization in Connecticut in 2012 for children ages 5 to 14, teenagers and younger adults, according to a new state health department report. The report shows that the number of days that patients with behavioral health problems were hospitalized surged 5.3 percent between 2011 and 2013, to nearly 260,000 patient days. Other categories of hospitalizations, including cardiac and cancer care, declined during that time. The data show five hospitals had increases of more than 12 percent in the number of days that patients with behavioral health problems were hospitalized. The biggest increases were at Yale-New Haven Hospital, which saw the number of patients rise 61 percent, and inpatient days jump 51 percent; and Waterbury Hospital, with 26 percent more patients and a 37 percent increase in inpatient days.