The most noticeable signs in a person suffering from PTSD are introversion and joylessness. People with this syndrome are unable to take pleasure from things they might have enjoyed in the past. They avoid the company of others and become generally more passive than before. They wish to avoid anything that will trigger memories of the traumatic event. A person with PTSD might drift out of a conversation and appear distant and withdrawn. This is known among soldiers as a "thousand-yard stare." This is a sign that unpleasant memories have returned to haunt them.
Having trouble sleeping is almost inevitable in this syndrome. Nightmares are common, and even when someone with PTSD is not thinking about the event, sleep is often disturbed. A common symptom among veterans is nocturnal myoclonus, a sudden spasm of the whole body while sleeping or drifting off into sleep. It lasts for about a fraction of a second, but may occur several times in a single night. Often people with PTSD will sleep through such a spasm, but their partner may not. Children with PTSD may have many nightmares, yet those dreams may not contain anything that's obviously related to the original trauma.
Psychiatrists speak of three symptoms that define PTSD – intrusion, avoidance, and hyperarousal. Intrusion is the inability to keep memories of the event from returning. Avoidance is an attempt to avoid stimuli and triggers that may bring back those memories. Hyperarousal is similar to jumpiness. It may include insomnia (trouble sleeping), a tendency to be easily startled, a constant feeling that danger or disaster is nearby, an inability to concentrate, extreme irritability, or even violent behaviour.
Depression is very likely to go hand in hand with PTSD, and in severe cases, suicide is a real danger. People with this syndrome, as with any psychiatric illness, are more likely than average to abuse alcohol or drugs. Psychiatrists see this as an attempt to self-medicate the condition, but naturally the drugs involved are very unlikely to improve the situation. People with PTSD are 2 to 4 times more likely to suffer from depression, anxiety, or substance abuse.