The PCLC is a screening test for Post Traumatic Stress Disorder (PTSD), developed by the US Military. It comes in active duty and civilian versions. Here is the civilian version: https://www.mirecc.va.gov/docs/visn6/3_ptsd_checklist_and_scoring.pdf.
This is a screening test, not a diagnostic test. I use it in clinic along with the PHQ-9 and the GAD-7, which respectively screen for depression and anxiety. There are also screens for ADHD and Bipolar Disorder, but I use those less.
The PCLC has 17 questions. Each question is scored from 1 to 5. The lowest score is 17 and highest is 85. Scoring any question at 3-5 is considered symptomatic. A positive screen has 1 or more answers at 3 or higher in the first "B" section, 3 or more at 3 or higher in the "C" section and 2 or more questions at 3 or higher in the third "D" section. Therefore the lowest positive is 3+9+6 and 1 in the seven other questions, =25.
A screening test is not a diagnosis. I use the three tests to help guide me with patients with depression or anxiety or insomnia. My choice of medicines is influenced by the tests. With really high scores, I encourage referral to behavioral health or psychiatry. I avoid addictive medications, or at least avoid starting them. The psychiatrist can handle that.
The highest score I see in the PCLC is not in a veteran. It is in an 80+ year old woman. I tested when she complains about sleep. Her score comes back at over 80. I am surprised. She states that she disappeared from her family forty years prior. I ask if she wants to talk about it. She says, "No." and I leave it alone. She escapes from a house fire with her walker in spite of a third degree burn. She is a survivor.
No screening test is perfect, but they can surprise me and they can open the door for discussion about what to do next. I have used the PHQ-9 to track a level of depression as well. For memory testing, I used to use the Mini-mental status test, but I've used the St. Louis University Mental Status Examination (SLUMS) and there are others: https://www.aafp.org/afp/2020/0615/od1.html.
I went to a number of lectures on PTSD the last time I was at a live conference. The most common cause in civilians is motor vehicle accidents, which surprised me. I thought it would be abuse, physical or sexual.