A surprising rise in student sobriety saw shares in Eclectic Bar Group tank on Wednesday, as the bars and nightclubs operator revealed a wider interim pre-tax loss.The AIM-listed company said its pre-tax loss in the six months to 28 December more than doubled to £525,000, citing increased competition, underperforming new sites and a smaller number of students drinking.Revenue rose 11.8% to £12.3m but the improvement was offset by increased operating costs, though the company said the performances were in line with its November estimates, when it issued a profit warning following a disappointing freshers' week period.The group said that its Lola Lo bar in Derby and the Dirty Blonde bar in Brighton had failed to meet targets and while it added that trading over the Christmas period had been encouraging, it warned that conditions remained difficult.Eclectic said there had been no return in mid-week sales since students returned towards the end of January, adding the current trend was likely to become a pattern for the foreseeable future."Whilst this has been a challenging period for the company, I am confident that the actions we have taken have made Eclectic a stronger company which will continue to build value for our shareholders over the medium term," said group chief executive Reuben Harley.Eclectic shares were down 45.84% to 50.10p at 09:56 on Wednesday.