Can post traumatic stress disorder ptsd lead to suicide?

Yes. A traumatic experience, by definition, temporarily overwhelms a person's ability to cope with it. Ptsd can be extremely distressing and long lasting if not treated properly. Suicide is an act of desperation to stop pain or distress that is unbearable when the person sees no other alternative. It is important to know there are effective ways to treat ptsd.
Yes - see link. The short answer is yes. A significant number of soldiers returning from war zones have been committing suicide. This has become of a major issue that the gov't is trying to address.
Yes. This is of significant concern in the military where suicides have risen in the wake of oif & oef. Post traumatic stress disorder (ptsd) is usually also associated with either depressed mood or clinical depression. Relentless nightmares and insomnia, combined with the exhaustion that results from non-stop hypervigilance heavily taxes one's reserves. Flashbacks can be completely debiltating.