Anxiety and depression are commonly encountered in primary care - and while I am certain that we underdiagnose these problems, i'll bet we overdiagnose them too - especially when we don't connect well with our patients. It's not uncommon for me to meet a new patient with a longstanding health problem who has been (unsuccessfully) treated with an SSRI by their previous physician for somatic complants with no clear cause.
I'll admit that sometimes the actions of the previous physician make sense to me - the patient with an anxiety disorder or depression who has persistent somatic complaints may very well be depressed or anxious - which is more likely the root cause of the fatigue or muscle pain than some rare biochemical disorder. Yet it's a tough line to walk - and sometimes people see a physician's attempt to treat depression as a cop-out in the context of a persistent somatic problem that feels (and is) very real.
There's no easy answer here. Depression is not a wastebasket diagnosis that we should throw at our patients when the TSH turns out to be nornal. Then again - we should not ignore it. Building an alliance with our patients to build a good understanding and shared decisionmaking can avoid such either-or dillemas.
I won't say I'm always successful at this .but I do try my best to walk this line in a respectful, caring manner.