Geoff Dempsey, aged 54, who worked at Dumfries High, was suffering from post-viral fatigue syndrome (ME) and complained that his condition became worse after being given a difficult third-year class.
Mr Dempsey had already had his working week reduced to five half-days because of his condition, an employment tribunal heard. Symptoms can include extreme exhaustion, muscle pain and severe flu-like malaise, difficulties with concentration and memory, loss of balance, sleep disorders and mood swings.
He felt there would be less strain and less fatigue if he was given more "teaching", or examination, classes and fewer with "discipline" problems.
He told the tribunal that for the first time he felt he was a danger to the class because of his inability to control it. If he had not had that class, he did not think he would have signed off sick. He retired on health grounds in April 2003.
Colin Mitchell, headteacher of Dumfries High, took issue with the proposition that Mr Dempsey should be given more examination classes since other members of the art department would be left with an unfair burden of non-examination classes.
Mr Mitchell also asserted that Mr Dempsey was frequently absent and colleagues often had to cover his classes. In these circumstances, he was reluctant to give him many certificate classes because their learning could be badly affected.
The head told the tribunal that classroom discipline was part and parcel of teachers' everyday life, and there were potential disciplinary problems in "teaching" classes. But Mr Dempsey accused Dumfries and Galloway Council of failing to make reasonable adjustments, including giving him more teaching classes and fewer difficult classes, under the Disability Discrimination Act.
The council argued that his working week had been cut, he continued to receive full salary, his registration class duties were taken away, the number of "please takes" was minimised and classroom support was arranged.
The tribunal found the council had made a number of adjustments but should have shared the burden of the difficult third-year class among other members of the art department. The tribunal found the council did not take reasonable steps to avoid Mr Dempsey suffering a substantial disadvantage and therefore unlawfully discriminated against him.
Mr Dempsey was awarded pound;58,361 in compensation, which included four years' loss of earnings from when he went off sick and pound;4,000 for injury to feelings.