Cat sleeping in litter box

Question
My female cat(4yrs old)  just began sleeping in the litterbox.  She will get out when my male cat needs to use it, but then she promptly returns and lays down in it and goes to sleep!  I'm not sure if she is trying to tell me something or if she is losing her mind...please help if you have any info that you could share.  Thank you. Teresa

Answer
I would be concerned that she doesn't feel well or has some anxiety since this is a new behavior.  I would take her to the vet for a check up and some blood tests.  I would also recommend adding another litter box or two (rule of thumb is one more box than the number of cats in the house) and try a cardboard box with a towel in it to see if she will lay in there instead.