Refers to mental distress, concerns, or troubles one carries. Often used in expressions like 煩いがある or 煩いの種.
Lately, work worries never cease.
He was freed from financial troubles.
Refers to physical illness or disease. Often used in compound words like 長患い (long illness) or with the kanji 患い.
After a long illness, he passed away.
Mental illness also affects the body.
lovesickness
nervous breakdown; neurosis; sickness from anxiety
Standard kanji for the worry/anxiety sense; also used broadly when the distinction is not important.
Specifically for illness/sickness; this kanji is especially for the illness sense.
Derived from the verb 煩う/患う (わずらう), meaning 'to worry' or 'to be ill'. The noun form わずらい nominalizes the verb stem.