There are multiple concerns associated with sleep:
Àô People suffering from PTSD have difficulty falling asleep and when they do, they most often have parasomnias (nightmares) in which they relive something similar to their injury. They awaken with a start, sometimes screaming, and cannot fall back asleep.
Àô People suffering from depression have trouble with sleep maintenance and awaken in the middle of the night (even though exhausted) and cannot fall asleep again.
Àô People taking narcotics will feel sedated, but their sleep is fretful and inconsistent.
Àô People taking some antidepressants, some anti-anxiety agents, and/or who drink alcohol since injury will have lengthy time in be without effective sleep.
The problems with sleep tell us not only about diagnosis_but about potential substance abuse.
They have in common that the patient is unrested, fatigued during the day and unlikely to effectively manage their pain and other complaints.