Pain and depression concomitant?

"According to a literature review, on average 63 % of patients with depression experience one or more pain complaint and depression is present in 5% -85% (depending on the study setting) of patients with pain conditions."

Link here
Commonly used tactic: If the LTD carrier cannot prove that you do not have pain, they will try to show that it is a mental problem due to presence of depression and they are therefore (typically) liable for 24 months.