The claimant was a chef. He split up with his long-term partner and had some child caring problems. He used annual leave and then sickness absence to deal with this. At some point he had sent a text to a manager in which he was “thinking about ending it all”. The claimant said it was his ex-partner who had sent this text. Nonetheless, the company doctor referred the claimant to a psychiatrist and the firm insisted on receiving a psychiatrist's report before allowing him back to work. He felt this was unreasonable and claimed constructive dismissal.  

The EAT found against the claimant. Not only was the employer's request reasonable in the circumstances, the claimant had failed to raise a grievance about the requirement and didn't give the employer an opportunity to deal with it. 
http://www.workplacerelations.ie/en/Cases/2015/April/UD1438_2013.html