Somatic Symptom Disorder, sometimes called Psychosomatic Disorder, is defined in the DSM V and does not mean the symptoms are "all in your head". It refers to patients with a compulsive-to-the-point-of-self-damaging focus on their condition, even if that condition is a diagnosed medical condition.

In other words, it's not a blank check to ignore these people.

More on SSD here: https://www.ncbi.nlm.nih.gov/books/NBK519704/table/ch3.t31 and here: https://www.ncbi.nlm.nih.gov/books/NBK532253