engleski

Neurobiology of posttraumatic stress disorder.

Posttraumatic stress disorder (PTSD) is a debilitating and severe, common psychiatric disorder, affecting 10% of all men and 18% of women. PTSD is a person’ s reaction to a life-threatening event that elicited fear, helplessness, or horror. PTSD is the only psychiatric disorder that requires an external event for diagnosis, however, the majority of individuals who experience severe trauma will not develop the disorder. Due to the increase of global conflicts and subsequent trauma exposure, PTSD will continue to increase in frequency. PTSD is, according to the DSM criteria, characterized by three divergent major clusters, contributing to complexity of its clinical presentation: symptoms of re-experiencing the event (intrusive thoughts, nightmares, flashbacks, and hyperarousal induced by reminders of the event) ; avoidance of stimuli associated with the trauma (avoiding activities, places, thoughts or feelings related to the trauma, as well as emotional numbing) ; and increased arousal (insomnia, irritability, impaired concentration, hypervigilance, and an exaggerated startle response). PTSD is a serious illness which includes functional impairment, occupational instability, marital problems, discord with family and friends, and difficulties in parenting. In addition, PTSD is often accompanied by substance abuse, and by different comorbidities, such as major depression, other anxiety disorders, somatization, personality disorders, and dissociative disorders. One of the major risk associated with PTSD diagnosis is frequent suicidal behavior. Combat-related PTSD is especially difficult and severe form of PTSD. According to USA data, around 830, 000 Vietnam war veterans still fulfill the diagnostic criteria for current PTSD, and within 31% of male and 27% of female veterans suffered from PTSD at some point during their lives after combat. The situation with current conflict in Iraq is even more serious, resulting in 13.18% of PTSD among active soldiers. During the Homeland war in Croatia, from 1991 to 1995, an estimated 1, 000, 000 of people (i.e. war veterans with combat-related PTSD and prisoners of war, but also traumatized civilians in the combat zones, displaced persons and refugees, victims of terrorist attacks, civilian relatives of traumatized war veterans and terrorist attacks victims, and traumatized children and adolescents) were exposed to a tremendous suffering, and about 10, 000 of the Homeland War veterans (15% prevalence) have developed PTSD. Between 57%-62% of 680 combat soldiers with PTSD had comorbid diagnoses, such as alcohol abuse, major depressive disorder, anxiety disorders, panic disorder and phobia, psychosomatic disorder, psychotic disorders, drug abuse, dementia, and suicidal behaviour. A proportion of combat veterans with PTSD have developed psychotic features, The neurobiological basis of PTSD is far from clear, although a significant improvement in the understanding of particular neurobiological alterations has been made in recent years. PTSD is characterized with persistent morphologic changes in the brain, and alterations in neurotransmitter and neuroendrocrine function. Neuroanatomical changes include reduced hippocampal volume in subjects with PTSD, and these morphological changes might explain divergent cognitive disturbances (i.e. of sensory and memory processing) found in PTSD. Neuroendocrine changes include dysregulated activity of the hypothalamic-pituitary-adrenal axis, with reductions in cortisol and elevations in corticotrophin-releasing factor secretion, and a supersuppression of cortisol after a low dose of dexamethasone. Alterations in different neurotransmitter systems (noradrenaline, serotonin, glutamate, γ -aminobutyric acid, and endogenous opioids) are associated with PTSD. Both neuroendocrine and neurotransmitter systems are regulated by multiple genes via proteins involved in the synthesis, degradation, transport, reuptake, receptors, and all these genetic, environmental, early traumatic and neurobiological factors, which are inter-correlated and interdependent. To elucidate the neurobiological basis of PTSD, and to designate heritable biomarkers that can serve as endophenotypes to improve risk assessment, diagnosis, and treatment strategies for PTSD, all these risk factors should be linked to smaller biological and psychological sub-symptoms that can serve as biomarkers of vulnerability and resilience.

neuroendocrine systems; neurotransmitter systems posttraumatic stress diosrder; combat veterans

Periodicum Biologorum 109 (2007) suppl 2 (0031-5362)