A person with mental illness may...

So you need to...

have trouble with reality

be simple, truthful,
not sarcastic

be fearful

stay calm

be insecure

be accepting

have trouble concentrating

be brief;  repeat

be over-stimulated

limit input, not force discussion

easily become agitated (not to be confused with dangerous)

recognize agitation,
allow retreat

have poor judgment

not always expect
rational discussion

be preoccupied

first get his/her attention

be withdrawn

initiate conversation

have changing emotions

disregard and have patience

have confused plans

stick to one plan

have little empathy for you

recognize this as a symptom

believe delusions

ignore or change the
subject;  don't argue

have low self-esteem and motivation

remain positive