There are too many ways depression manifests to say that a person with PCS either does or does not suffer from depression. Depression does not always included the negative ideations that include suicide, etc. There are overlaps between PCS and depression that also make a diagnosis difficult.
The important fact is that depression is very common within the PCS community so the injured, family and friends need to b e informed and ready to seek professional help.
jinga, I think both of your ideas are correct. The PCS can cause the issues that lead to depression and can simply cause the brain to succumb to depression due to its malfunctions.
A simple way to define the causes of depression is this: It is the result of the brain being over-worked or over-stimulated to a point where it fatigues and becomes overwhelmed with the toxins left by such efforts. It is know that too much pleasurable stimulation can lead to depression just like you can wear out your muscles doing pleasurable efforts and doing uncomfortable efforts.
The concussed brain has less tolerance for these stressors.
Mark in Idaho
58 years old, retired due to disability, married 33 years, father of three, grandfather of four, Suffered a serious concussion at 10 years old (1965) stopped most driving after last concussion at 46 years old (2001), Post Concussion Syndrome/Multiple Concussion/Impact Syndrome with PTSD, immediate and short term visual and auditory memory problems, slowed processing speed, visual and auditory processing difficulties, insomnia, absence seizures, OCD, 14 concussions since first concussion at 8 years old, Taking paroxetine and gabapentin for 12 years. Added L-Tryptophan and reduced paroxetine by half 3/2013
"Be Still and Know That I am God" Psalm 46:10