In certain circumstances, yes it can, says the EAT in in Osei-Adjei v RM Education.
In this case the employment tribunal found that the Claimant suffered an act of disability discrimination by reason of the Respondent's failure to make a reasonable adjustment. The Claimant suffered a psychological injury (depression) that was triggered by this failure. However, at the time of the Claimant's resignation his health had improved, he had been pronounced medically fit to return to work, his job was open to him, and all reasonable adjustments had been made or would be made to enable him to resume his employment. The Respondent's failure to make a reasonable adjustment did not cause the Claimant's resignation. In those circumstances the employment tribunal was entitled to find that the resignation had broken the chain of causation in respect of any future loss of earnings.
In reference to a cross-appeal by the Respondent, the EAT held that where an employee suffers injury for which their employer is only partly to blame, compensation for that injury should be assessed by reference to the relative contribution of the employer in question. On the facts of this case there were additional factors causing the Claimant's depression and the Respondent's responsibility for the injury was assessed as being 40%.