Thanks for using the forum. I am happy to address your questions, and my answer will be based on the information you provided here. Please make sure you recognize that this forum is for educational purposes only, and it does not substitute for a formal office visit with your doctor.
Without the ability to examine your room mate and obtain a history, I can not tell you what the exact cause of her symptoms is. However I will try to provide you with some useful information.
Some people have what is termed an exaggerated startle response, in which even light sounds can cause a startle response. This is not necessarily an abnormal finding. However as you allude to above, in some people, excessive startle can be a sign of an underlying problem. In people who have suffered
psychologicalChild neglect and psychological abuse or physical trauma, post-traumatic stress
disorderAdjustment disorder
Anorexia nervosa
Asperger syndrome
Autism
Autoimmune disorders
Bipolar disorder
Bipolar disorder
Bleeding disorders
Borderline personality disorder
Bulimia
Chronic motor tic disorder (PTSD) can occur and one of the features of this is hypervigilance. The symptoms you describe of lethargy and loss of energy could be features of depression. Of course, they may also reflect poor sleep etc. and may not necessarily reflect an underlying problem. However, I recommend discussion of your concerns with your room mate, and encourage her to seek appropriate
mentalMental retardation
Mental status tests health services. Sharing the concerns with a counselor at the institution is important, while of course maintaining her privacy.
Thank you for this opportunity to answer your questions, I hope you find the information I have provided useful, good luck.