Ibrahim Abu Nada (1)

Objective: This study investigates the impact of ongoing traumatic events on Palestinian adolescents’ posttraumatic stress according to event-related and demographic factors. Method: A sample of 368 Palestinian adolescents (49.2% males, mean age 17.03) was drawn from different areas of the Gaza Strip. Students were investigated on exposure to traumatic events and posttraumatic stress symptoms (PTSS) and disorder (PTSD). Results: The mean number of traumatic events experienced by the adolescents was 9.9 (SD = 3.20). Boys were significantly more exposed than girls, as were adolescents living in villages compared to those living in Gaza city or refugee camps. Adolescents mainly and pervasively experienced objective, non-personal material exposure (such as witnessing bombardments) (85% to 96%) and media exposure (95%). Up to 17% of the adolescents experienced direct, physical exposure (7% personal injury), exposure through injury and death of relatives. In this context, two fifths of the adolescents experienced mild, two fifths moderate and one fifth severe PTSS. Remarkably, adolescents did not differ significantly in PTSS despite exposure differences across gender, place of residency and family income. Conclusion: Near half of the investigated adolescents living in the Gaza Strip experience moderate to severe levels of posttraumatic stress, for around one fifth this amounts to a probable posttraumatic stress disorder. These findings urge toward providing psychological support programs to Palestinian adolescents to enhance current wellbeing and limit further developmental risks. Furthermore, the findings suggest the need to investigate the role of appraisal and coping to understand the pathways through which differences in trauma exposure lead to similar posttraumatic stress outcomes.


Introduction
Since the outbreak of the al-Aqsa I ntifada in late September 2000, Palestinian youth hav e been extensiv ely exposed to traumatic ev ents.These hav e ranged from w itnessing bombardment of homes, schools and streets, through hearing about the killing of friends and relativ es, to being personally injured.Such ongoing exposure raises questions about the psychologic al effects it exerts on adolescents.Exposure to traumatic ev ents is know n to increase the risks of both short-term and long-term mental health problems (Saigh, 1991;Thabet, Abed, and Vostanis, 1999).Youngsters liv ing in conditions of w ar and military v iolence hav e been described as grow ing up too soon and taking premature political responsibilities (Boothby, Upton, Sultan, 1992).They are also know n to be at high risk of dev eloping posttraumatic stress symptoms or disorder (PTSS/PTSD) (Dyregrov , Gjestad, and Raundalen, 2002).I n the past years, research about psychological outcomes after traumatic ev ents has increased.How ev er, relativ ely few studies specifically examine how adolescents" continuing exposure to trauma impacts on their w ellbeing.Also, research conducted so far has remained inconclusiv e as regards the range and the intensity of these outcomes according to ev ent-related and demographic determinants.
This study examines the prev alence of posttraumatic stress in Palestinian adolescents liv ing in the Gaza Strip.I t also inv estigates to w hat extent these youth"s stress reactions v ary according to ev ent-related and demographic factors.To this effect, w e shall first briefly discuss the state of the literature regarding adolescents" PTSS after exposure to traumatic ev ents and potential determinants in this context.
Posttraumatic stress in the face of chronic exposure to trauma: From theory to empirical ev idence Briefly circumscribed, posttraumatic stress consists of typical reactions that arise after experiencing "sev ere" traumatic ev ent(s) or situation(s).They mainly include intrusiv e re-experiencing of the ev ent(s), hyper arousal, and av oidance and numbness symptoms.The persistence hereof for more than a month w ill amount to a posttraumatic stress disorder (PTSD) as described by the DSM -I V diagnostic criteria Europe's Journal of Psychology 34 (American Psychiatric Association, 2004; also see I nstruments).From a more dynamic bio-psycho-social approach as conceptualized in the FACE © -model (Facilitating Adjustment of Cognition and Emotion), posttraumatic stress amounts to a series of cognitiv e and emotional adaptations reflecting the exposed indiv idual"s attempts to deal w ith ov erw helming stressor(s).Posttraumatic stress is thus conceiv ed as the more or less durable disruption, follow ing traumatic experiences, of the adjustment betw een cognitiv e control and emotion regulation processes, w ith the first being bypassed (e.g. as regards executiv e functioning, memory and attention processes) by an intensified reactiv ity and modified biochemistry of the latter (e.g. as regards autonomous reactions, neurotransmitter functioning and neuronal connections) (Celestin-Westreich and Celestin, 2010).Ov erall, the ev idence-base has demonstrated dose-response effects to this regard, namely, higher exposure lev els trigger higher posttraumatic stress lev els.How ev er, w hile some ev ents or situations w ill be ov erw helmingly traumatic to most indiv iduals, important v ariability also exists as to w hich experiences are traumatic to w hom, to w hat extent and under w hich circumstances (Braun-Lew ensohn, Celestin-Westreich, Celestin, Verleye, Verté, and Ponjaert-Kristoffersen, 2009a;Celestin-Westreich and Celestin, 2010;Kalantari and Vostanis, 2010;Pow ers, Halpern, Ferenschak, Gillihan, and Foa, 2010).From the abov e-cited FACE © perspectiv e, this happens as a function of the balance of personal, relational and env ironmental risk factors and resources for a giv en indiv idual at a giv en time as w ell as throughout the life span.
For adolescents, posttraumatic stress prov es crucial to their dev elopmental pathw ays.Adolescence indeed tends to imply both sources of resilience and v ulnerability tow ard PTSS/D.On the one hand, youngsters" brains are still dev eloping w hich may facilitate resiliency through neuroplasticity, especially w hen supported by proper prev ention and interv ention strategies.On the other hand, particularly from middle adolescence on, strong stressors may precipitate preexisting difficulties and/or (genetical) predispositions tow ard div erse forms of psychopathology.
Posttraumatic stress may therefore interfere in multifinal w ays w ith middle to late adolescents" dev elopmental tasks of distancing from parents and family, experimenting w ith div erse roles and identities in society and engaging tow ard adult functioning, the more so in societies w here such roles are taken up relativ ely early in life.For example, trauma exposure may prov oke procrastination in some adolescents w hile aggrav ating acting out in others.Hence, posttraumatic stress reactions during adolescence are nev er negligible (e.g.Cummings, Dav ies and Campbell, 2000;Finkelhor, 1995;Pow ers et al., 2010;Qouta, Punamaki, Montgomery, and El Sarraj, 2007).(PCBS, 2006).Ov erall, PTSS lev els seem to range from 10% to 70% among the youth from the Gaza strip (Thabet et al., 1999;Qouta, Punamaki, and El Sarraj, 2003).I n a study on 1000 school-aged Palestinian children, 54.7% reported experiencing at least one intense traumatic ev ent in their lifetime and 34% w ere diagnosed as hav ing full PTSD (Khamis, 2000).I n child populations from relativ ely comparable contexts, lev els of PTSS ranged from 22 to 25% among I sraeli and 27% among Lebanese children, through 48% among Cambodian refugee children and 52% among Bosnian youth (Kinzie, Sack, Angell, Manson, and Rath, 1986;Smith, Perrin, Yule, and Rabe 2001).I raqi children w hose shelter w as destroyed by shelling show ed the highest posttraumatic stress lev els (78-88%) (Dyregrov et al., 2002).

Posttraumatic stress among
The few studies specifically pertaining to Palestinian adolescents (aged 11 to 19 years) suggest that 11 to 16% suffer from low to mild, 33% to 49% from moderate and 33 to 54% sev ere lev els of PTSS/D (e.g.Qouta et al., 2003).
Giv en these data, closer inv estigation is required to understand the w ide range of posttraumatic stress reactions among Palestinian youth.For one, "posttraumatic stress" lev els tend to be div ersely circumscribed across and ev en w ithin studies, including either posttraumatic stress symptoms (PTSS), disorder (PTSD, as defined by DSM criteria) or both.I n short, there is a need to distinguish betw een PTSS and PTSD w hen reporting Palestinian adolescents" posttraumatic stress lev els.Furthermore, to date these lev els hav e mainly been inv estigated as a function of the degree of exposure.The broader trauma literature suggests that PTSS outcomes may also v ary according to types of exposure, personal and other demographic factors (such as gender, age, and place of residency and fami ly characteristics), as discussed hereafter.
The role of lev els of exposure Regarding lev els of exposure, the dose-response effects expected from the general trauma literature tend to be found in most studies on Palestinian youth.For example, w hen examining Palestinian children"s (aged 9 to 16 years) responses to v arying intensities of socio-political v iolence during the past six years, mean PTSS rates ev olv ed from 40% after the end of the first intifada in the peace period, through 10% during the peace process and up again to 39% during the current intifada.PTSS peaked to 70% during recent shelling of the Gaza Strip (Thabet et al., 1999;Thabet, and Vostanis, 2000;Thabet, Al Gamal, Vand Vostanis, 2006;Thabet, Abu Taw ahina, El Sarraj, and Vostanis, 2007).W hen comparing Palestinian and I sraeli-Palestinian children"s reactions to exposure to traumatic ev ents, ov er one third of the former displayed sev ere to v ery severe PTSS compared to one fifth of the latter (Tamar and Solomon, 2005).Furthermore, some ev idence also suggests a decrease in PTSS w hen the exposure subsides.This w as the case, for example, w ith school-aged I sraeli children w hose PTSS dropped from 22% to 12% in one year w hen scud missile attacks ceased after the Gulf War (Schw arzw ald, Weisenberg, Waysman, and Solomon, 1993).PTSS also decreased in a 30-month follow -up among displaced I sraeli preschool children (Laor, Wolmer, Mayes, Gershon, Weizman, and Cohen, 1997).
How ev er, such trends are not necessarily linear.For example, PTSS w as first found to increase among Iraqi children during the 13 months after their shelter had been bombed, to fall significantly only after tw o years (Dyregrov , and Raundalen, 1993).I n short, exposure lev els and more specifically dose-response effects w arrant attention w hen attempting to understand posttraumatic stress responses in youth.Still, the current literature limits draw ing conclusions about the persistency v ersus attenuation of symptoms because the types of trauma, length of follow -up, children"s gender and age w idely differ across studies.Especially regarding the latter, it should be noted that only few published studies appear to specifically pertain to Palestinian adolescents.
The role of types of exposure Types of exposure merit further analysis giv en an increasing ev idence-base on trauma resulting from military v iolence and socio-political adv ersities.More specifically, exposure in this context can be sub-typed into objectiv e, subjectiv e and media exposure (Braun-Lew ensohn et al., 2009a).Objectiv e exposure consists of observ able facts that cannot be controlled by the indiv idual.I t can be further subtyped in direct, physical exposure and indirect exposure (through w itnessing and relationship w ith a v ictim).Subjectiv e exposure refers to the indiv idual"s experience of the ev ents (immediate appraisal), regardless of their objectiv e characteristics.
Media exposure merits separate attention giv en its mix of both objectiv e and subjectiv e characteristics.I ndeed, w hile w atching the media implies some extent of objectiv e exposure (namely w atching real images of shelling, shooting and so forth), it is also partly controlled by the indiv idual"s choice to consult the media.I n the Palestinian context, shifts in types of exposure may apply betw een the first (1987) and the second (2000) Al Aqsa I ntifada.During the first I ntifada, objectiv e exposure appeared predominant in both its indirect-relational and direct-physical components, as ev idenced by the frequency of tear gas attacks (93%), breaking into homes (90%), beatings of family members or self (70% to 62%) and being personally injured (37%) (Abu-Hein, Qouta, Thabet, and El-Sarraj, 1993).Research closer to the current study period suggests a shift tow ard the predominance of media and indirect, relational objectiv e exposure.For instance, across studies, ev ents cited by tw o-thirds to more than 90% of Palestinian children include seeing v ictims of v iolence on telev ision, w itnessing funerals, shootings, bombardments and shelling and injured or dead persons.A s maller proportion of youngsters report being shot by bullets (12.9%) (Qouta et al., 2003;Thabet, Abed, and Vostanis, 2001).
Adolescents" objectiv e exposure to higher lev els of physical traumatizing ev ents has been, understandably, found to elicit more adv erse psychological reactions, including higher rates of PTSD, functional impairments, anxiety and substance abuse.
Research how ev er also has show n that media and indirect objectiv e exposure also strongly contribute to youth"s PTSS (Braun-Lew ensohn et al., 2009a, 2009b;Dyregrov et al., 2002;Punamaki, Komproe, Qouta, ElMasri and de Jong, 2005;Thabet & Vostanis, 2000).Taken together, these findings suggest that types of exposure may require attention w hen attempting to understand adolescents" psychological responses to ongoing trauma.

The role of gender
Regarding gender, girls generally appear to be more v ulnerable tow ard PTSS than boys (Dyregrov et al., 2002;Braun-Lew ensohn et al., 2009;Orla, 2003;Orlee, Boyle, and Yule,2000).Although this tendency also comes forw ard in the Palestinian context (e.g.Punamaki,and Puhakka, 1997;Qouta et al., 2003, Qouta, Punamaki, andEl Saraaj. 2004;Thabet et al., 2001), its extent remains equiv ocal, w ith some studies suggesting no gender differences or ev en higher lev els of posttraumatic stress in males, as in Punamaki et al." (2005) study on peritraumatic reactions.Age may play a role in these mixed findings, since gender differences appear prev alent in studies focusing on the broad childhood period, as opposed to Punamaki et al"s findings among 16 to 60 year olds.The extent of gender effects may also be trauma specific (e.g., natural disasters v ersus societal trauma) (Punamaki et al., 2005;Saigh, 1991;Thabet, Abu-Nada, Shiv ram, Millingen, and Vostanis, 2009).Thus, posttraumatic gender effects specifically among Palestinian adolescents merit further clarification.

The role of the current age cohort
The extent and type of age effects in youth"s responses to chronic trauma exposure hav e remained equiv ocal too.W hile some studies hav e not found any age effects in such contexts (Saigh, 1991), according to others, both younger and older children appeared to be more v ulnerable than their counterparts (e.g.Qouta et al., 2003).A child's age, therefore, may not be a risk factor in and of itself; rather, in each grow th and dev elopmental stage children and adolescents deal w ith both resiliencies and v ulnerabilities (Berman, 2001;Braun-Lew ensohn et al., 2009;Celestin-Westreich and Celestin, 2010;Finkelhor, 1995;Punamaki, 2002).Notably, the current cohort of Palestinian adolescents is characterized by hav ing liv ed more than tw o thirds of their youth under ongoing traumatic ev ents, hav ing been around 10 years old w hen the current Al-Aqsa I ntifada erupted in 2000.This i mplies a pronounced degree of v ulnerabilities experienced throughout their childhood that may contribute tow ard elev ated PTSS lev els.
The role of other demographics I n an attempt to further differentiate influencing demographic factors, mainly place of residency has been considered through its simultaneous link w ith levels of exposure and env ironmental specificities.The Palestinian area of residency is mainly subdiv ided into Gaza city and refugee camps (both situated far aw ay from the borders) and v illages (close to the borders).Compared to those liv ing in the v illages, youth from Gaza cities or refugee camps are less likely to be exposed to physical incursions or artillery bombardments, but more to aircraft bombardments on homes, gov ernmental buildings and streets (PCBS, 2006).The effect of place of residency on youngsters" PTSS has nonetheless yielded unclear findings to date.Thus, in one study Palestinian children liv ing close to Israeli settlements w ere found to show acute lev els of posttraumatic stress to an important extent (55%) (Quota et al., 2005), w hile other research found children meeting the criteria of PTSD to come mainly from urban areas (Thabet et al., 2001).Furthermore, the literature ev idences that adolescents in w ar zones can be affected through v arious other demographic influences, such as a lack of basic health needs, loss of family members, disruption of social netw orking and displacements.Few studies hav e examined the relationship betw een such demographical characteristics and the lev el of PTSS among adolescents in the Palestinian society (Qouta, Punamaki, and El Sarraj, 1997;Thabet, Abed, and Vostanis, 2002).
I n short, env ironmental and family demographic characteristics still need to be more extensiv ely addressed w hen inv estigating Palestinian adolescents" posttraumatic responses.

I mplications for current research
As comes forw ard from the current state of the literature, many aspects of adolescents" stress reactions to a chronic context of exposure to socio-political v iolence w arrant further inv estigation.To this effect, the follow ing research questions and hypotheses w ere addressed in the present study.I t appeared relev ant to first inv estigate lev els and types of exposure, along w ith possible demographic v ariations hereof.Giv en the current ev idence-base, w e expected a majority of the Palestinian adolescents to hav e been exposed to more than one objectiv e traumatic ev ent.
Giv en that the demographic and env ironmental characteristics of the Palestinian society hav e remained relativ ely understudied, possible differences in exposure according to place of residency and family demographics w ere to be explored.Our primary research goal then pertained to identifying the lev els of posttraumatic stress specifically for Palestinian adolescents, w ith the expectation of these being higher than those in non-exposed populations.Finally, w e set out to identify demographic factors that may affect these adolescents" PTSS.We hypothesized that girls w ould demonstrate higher lev els of PTSS than boys, as w ould adolescents in higher exposed places of residency.Also, w e hypothesized Palestinian adolescents" PTSS to be inv ersely correlated to family and env ironmental resources (the low er the resources, the higher the PTSS).

Method Participants and context
This study comprised a sample of 368 Palestinian adolescents ( 11 th Grade; M = 17.3 years; 49.2% male) liv ing in the Gaza Strip, w hich is approximately 50 kilometers long and 5 to 12 kilometers w ide.The Gaza strip spans a narrow zone of land along the Mediterranean Sea, betw een I srael and Egypt.The total population is one and a half million w ith a population density of 2.150 people per kilometer.Among these, 808.000 persons are registered refugees, ov er 55% of w ho liv e in eight refugee camps scattered across the Gaza Strip.Other inhabitants liv e in v illages and cities of the Gaza Strip.The United Nations for Relief and Work Agency (UNRWA) prov ides education for 159.892 pupils, as w ell as health and relief serv ices to refugees liv ing inside and outside the camps (Thabet et al. 2006).Among the participants studied, 60% w ere refugee adolescents liv ing in Jabalia refugee camp, w hich w ith a population of approximately 120.000, lacks basic infrastructure.Approximately one fifth (21%) of the adolescents w ere from Bet-Hanon v illage, w hich is situated in a remote part of the Gaza Strip (close to the I sraeli borders) and has around 45.000 inhabitants.The remaining adolescents (19%) w ere from Al-Remal city, w hich is a relativ ely more prosperous urbanized neighborhood of approximately 30.000 inhabitants.

I nstruments
Participants completed a standardized battery that included the follow ing questionnaires aimed at examining the initial hypotheses.
"Demographic & Socio-Economic I nv entory" Demographics w ere assessed by using a self-designed inv entory that included questions regarding gender, place of residency, family size, family income, maternal and paternal education and occupation.

Gaza Traumatic Ev ent Checklist (GTEC)
The GTEC w as used to assess participants" exposure to traumatic ev ents ov er the last six months.I t consists of 20 traumatic ev ents that commonly occur during the ongoing political and military v iolence in the Gaza Strip.The initial v ersion w as dev eloped by the research department of the Gaza Community Mental Health Program (GCMHP) and has been used in prev ious studies on Palestinian children (Thabet et al. 1999(Thabet et al. , 2002)).I tems require dichotomous answ ers, yielding a range of total trauma scores from 0 to 20.This checklist has show n satisfactory split half reliability (R = 0.776) and internal consistency (Cronbach"s alpha = 0.749), Thabet et al. 2002;2009).

The Dav idson Trauma Scale (DTS)
The DTS is a self-rated scale, comprising 17 items designed to measure posttraumatic stress reactions in youngsters aged 6 to 18 years.Tailored closely to the symptom definitions of the Diagnostic and Statistical Manual of Mental Disorders, 4th edition (DSM-I V), these pertain to intrusiv e re-experiencing (DSM-IV criteria B), av oidance and numbness (DSM-I V criteria C) and hyper arousal reactions (DSM -I V criteria D) (American Psychiatric Association, 1994).Before application, adolescents must meet DSM-IV criteria A and E, namely experiencing or w itnessing an extremely traumatic ev ent.Rating is ordinal (from "nev er" (0), through "sometimes" (1) to "often" ( 2)).
Participants w ere giv en a "probable current PTSD diagnosis" if they responded w ith "often" to at least one of the four "trauma re-experiencing" items, along w ith at least three of the sev en "av oidance of stimuli associated w ith trauma" items and at least tw o of the six "increased arousal" items.The DTS theoretical sum score range lies betw een 0 and 34.I n our sample, this range w as further grouped into "none or doubtful" (score 0-8), "mild" (score 9-16), "moderate" (17-24) or "sev ere" (25 and abov e).The DTS has been translated into Arabic by professional bilingual translators.I t show s satisfactory reliability w ith a split half R of 0.74 and internal consistency Cronbach"s alpha of 0.75 (Thabet et al. 2002, Thabet et al. 2009).The reliability in our sample also show s satisfactory w ith a split-half R of 0.605 and Cronbach"s alpha of 0.709.

Procedure
The ethical procedures applicable to this study w ere follow ed.As required by the Palestinian Ministry of High Education, the research proposal and questionnaires w ere submitted before the start of the study.After receiv ing their approv al to proceed, permission to enter the schools w as gathered from the principals.Students completed the self-report questionnaires during regular class hours in the first trimester of the academic year 2006-2007.Students w ere introduced to the study purpose and assured of the confidentiality of all data.The participants w ere informed that the researcher w as interested in their experience of ongoing traumatic ev ents, that participation w as v oluntary and anonymous, and that they w ere free to w ithdraw their participation for any reason and at any time during the questionnaire procedure.Completion time ranged from around 35 to 45 minutes.
As indicated, data w ere gathered from secondary schools located in the area of Jabalia refugee camp, Bet-Hanon v illage and Al-Remal city.A multistage random sample design w as used to reach the potential study sample, in three main phases.
First, cluster random selection w as applied to include all the gov ernmental secondary schools in the abov e cited areas.Second, stratified cluster selection w as applied on classes in w hich the students had been giv en a participation inv itation (450 adolescents).Third, among those w ho obtained parental consent and agreed to participate, adolescents w ere randomly selected by choosing those sitting on the right side of the classroom desk.Thus, a representativ e sample of 368 Palestinian adolescents w as draw n from a total of 4551 students, distributed ov er 115 classes (11 th grade) from 13 gov ernmental secondary schools.
To av oid any dramatic changes in the political situation in Gaza that might hav e affected the adolescents" responses, all data w ere gathered w ithin a time frame of tw o consecutiv e w eeks.The response rate w as considered to be satisfactory, w ith 98% of the inv ited adolescents agreeing to participate in the study.

Data analysis
Analyses w ere computed using the statistical softw are SPSS v ersion 13.0.The data w ere analyzed using descriptiv e and inferential analysis.The present analyses assessed sev eral predictors (i.e., lev el of exposure to traumatic ev ents and demographic factors) for the outcome v ariable "posttraumatic stress reactions".The inferential analyses included use of independent sample t-tests and one-w ay ANOVA.

Results
Demographics: descriptiv e Consistent w ith the Palestinian demography, participating adolescents w ere from "large" families w ith 72% comprising nine family members or more.
The v ast majority of these families are characterized by low socio-economic lev els (educational and employment), w ith 57.6% of fathers and 69% of mothers hav ing completed low education (secondary school or less) in contrast to 21.5% of f athers and 13.9% of mothers hav ing completed higher education (univ ersity graduation to postgraduate).Ov er one third of the adolescents" fathers w ere unemployed, w hile approximately one fourth w orked as civ il employees and the remainder as laborers.
Approximately, four fifths of their mothers w ere house w ives, slightly less than one fifth employees and the remainder laborers.Due to high lev els of unemployment, 42% of the adolescents" families earn less than 100 euro's a month.This study first set out to examine the adolescents' lev els and types of exposure to traumatic ev ents.The mean number of traumatic ev ents that any particular adolescent experienced w as 9.9 (SD = 3.20).Table 2 furthermore show s that the v ast majority of the adolescents w ere exposed to objectiv e indirect traumatic ev ents (implying no personal physical harm and not directly pertaining to their family) as w ell as media exposure.A smaller, yet sizeable proportion of adolescents w ere exposed to direct physical harm, through relationship w ith a v ictim, or material harm to personal belongings.The numbers and percentages of adolescents endorsing an item are given by row.
Respondents can endorse as many items as relevant on the GTEC.
Finally, only family income w as significantly associated w ith the degree of exposure to traumatic ev ents.Thus, w e observ ed a negativ e linear trend betw een lev el of family income and number of traumatic ev ents (r = -.16;p = 0.002).Note: Exposure is classified in mild (<4 events), moderate (5-10 events) and severe (>11 events) (Thabet et al., 2001(Thabet et al., , 2008) ) Lev els of posttraumatic stress The primary goal w as to assess adolescents" posttraumatic stress lev els.Our results indicate that only less than one-tenth (9.8%) of the adolescents show ed no PTSS, w hereas the majority show ed mild to moderate (40.5% and 44,3% respectiv ely) and 5.4% sev ere PTSS.Taken together, this corresponds to 17.1% of the participants displaying symptoms amounting to a probable PTSD according to DSM-IV diagnostic criteria.

Discussion
This study set out to examine Palestinian adolescents" posttraumatic stress and possible situational and demographical determinants hereof.To do so, the lev els and types of exposure, along w ith v ariations across personal, env ironmental and family demographics needed to be explored first, as discussed hereafter.
Lev els and types of exposure On av erage, the inv estigated 17-year old Palestinian adolescents had experienced around ten traumatic ev ents during their lifetime.These findings are consistent w ith prev ious research show ing that Palestinian youth hav e experienced significant exposure to socio-political v iolence (Macksoud, Aber, and Cohen, 1996;Punamaki, Qouta, and El Sarraj, 1997;Quota et al., 2005;Thabet et al., 2001).According to the classification of exposure lev els conv ened by a consensus meeting of Palestinian mental health professionals, this corresponds to a mean lev el of modera te-to-sev ere exposure (Thabet et al., 2001(Thabet et al., ,2008)).
The v ast majority of the inv estigated adolescents w ere exposed to objectiv e yet indirect traumatic ev ents (no personal physical or family harm) and media exposure, consistent w ith the expectation of a shift in type of exposure in this age cohort.The high lev els of media exposure may furthermore indicate a lack of leisure activ ities for adolescents (Thabet et al., 2001).
Variations in lev els of exposure according to demographics Primarily, adolescents" gender and place of residency determined lev els of exposure to trauma, w ith boys and those liv ing in the v illages experiencing more traumatic ev ents.These findings appear consistent w ith other research (Qouta, Punamaki, and El Sarraj, 1995;Punamaki et al., 2005).Regarding gender, this difference in exposure may result from Palestinian girls being culturally more sheltered (kept inside the homes) and less likely to participate in political activ ities compared to boys.As indicated before, the higher exposure for adolescents liv ing in v illages seems to result from the political implications of their geographical location.These findings may also suggest cohort influences, as they are consistent w ith the more recent research suggesting higher lev els of exposure for children liv ing in the rural area compared to earlier findings show ing no relation hereof w ith place of residency (Qouta el al., 1995).Not surprisingly, low income families disposing of lesser resources w ere also at risk for higher lev els of exposure to traumatic ev ents, consistently w ith findings, for example, among low income families in Lebanon (Macksoud, 1996).Whether the absence of significant relationships of lev els of exposure w ith the other family demographics is robust or dependent on the ov erall lev els of exposure remains to be further inv estigated.

Lev els of posttraumatic stress among Palestinian adolescents
Our main goal w as to assess the lev els of posttraumatic stress among the Palestinian adolescents.As expected, these appeared to be high, amounting to around one fifth of the adolescents displaying probable PTSD and a v ast majority of them suffering from substantiv e re-experiencing, av oiding, and arousal symptoms.Giv en these adolescents" high lev els of trauma exposure, these findings appear consistent at first sight w ith the current literature base concerning dose-response effects.
Considering that their exposure included high lev els of indirect objectiv e events and the mixed-type media exposure, the findings especially concur w ith research show ing that these types also exert adv erse effects in settings of prolonged indiv idually and collectiv ely experienced sociopolitical v iolence.By themselv es, these findings w arrant the dev elopment of prev ention and interv ention programs geared at informing youth about PTSD and its implications and helping them deal w ith it (Braun-Lew ensohn et al., 2009a;Celestin-Westreich & Celestin, 2010;Elbedour, Anthony, Ghannam, Janine and Abu Hien, 2007;Pow ers et al., 2010;Quota et al., 2007;Thabet et al., 2007).

Posttraumatic stress symptoms according to gender
The absence of significant gender differences in PTSS in our sample, despite boys" significant higher trauma exposure, in turn, appears to contrast w ith the general literature-based expectations.At closer analysis, it may result from a compensation effect, w ith boys" higher exposure contributing to higher PTSS, thus lev eling out girls" typically higher PTSS lev els.Together w ith the earlier discussed equiv ocal outcomes to this regard in the Palestinian context, our results may also suggest the need to take into account the contextual factors w hen considering gender effects.For example, a further explanation may lie in the combination w ith the age cohort, w hereby dose-response effects possibly attain a ceiling after chronic exposure and thus lev el out stress responses betw een boys and girls.

Posttraumatic stress symptoms according to demographic factors
The inv estigated adolescents furthermore did not differ significantly in PTSS lev els across place of residency, despite v illage residents being more exposed than refugee camp and city residents.These findings are consistent w ith some studies conducted on Palestinian children, w hich document more sev ere PTSS among children w ho are liv ing in the more exposed areas such as those close to I sraeli settlements, but not w ith others that document more PTSS in the urban areas or in refugee camps (Elbedour., 2007;Qouta et al., 2004;Thabet et al., 2002Thabet et al., , 2009)).
Adolescents" PTSS-lev els w ere not affected either by the negativ e link betw een family income and exposure lev els.The absence of linkages w ith any of the other inv estigated demographics (such as family size, parental education and occupation) remains consistent in the first place w ith the absence of any differences in lev els of exposure to this regard.
Taken together from the aforementioned risk-resiliency FACE model"s perspectiv e of youth"s cognitiv e-emotional adjustments to trauma exposure, ceiling effects in the dose-response principle may prov ide a first explanation for a fading out of PTSSdifferences among adolescents hav ing experienced prolonged indiv idual and collectiv e exposure throughout childhood, ev en w hen coming from v ariously exposed residency and family income backgrounds.Stated differently, although not mutually exclusiv ely, mediating dynamics such as adolescents" primary attribution and coping processes, may lead to equifinal PTSS outcomes across circumstances through different cognitiv e and emotional pathw ays, as ev idenced in dev elopmental psychopathology and recent research specific to chronic trauma exposure (Braun-Lew ensohn et al., 2009a, Braun-Lew ensohn et al., 2009b, Celestin-Westreich and Celestin, 2010;Cummings et al., 2000;Elbedour et al., 2007;Pow ers et al., 2010;Qouta et al., 2007).Ev idently, such assumptions need to be tested in further research.

Study limitations and future direction
Sev eral limitations apply to the present study.First of all, the data w ere not gathered from multiple data sources (e.g., teachers, parents, peers), but w ere based only on adolescents" ow n ev aluations.The multi-informant method w ould contribute to achiev ing a more complete ev aluation of these youths" functioning.Also, it should be noted that no Palestinian control group w as av ailable since the w hole Palestinian population is affected by the ongoing Al-Aqsa I ntifada.Particularly, this study utilized a cross-sectional design and, thus, it is difficult to infer any cause-effect relationships.
Finally, since only 11 th grade or 17-year old adolescents w ere inv estigated, different outcomes may apply to younger or older adolescents.

Conclusion
This study analyzed the impact of ongoing traumatic sociopolitical ev ents on Palestinian adolescents" posttraumatic stress reactions (PTSS and PTSD) accor ding to ev ent-related and demographic factors.
The inv estigated 11th grade adolescents experienced a mean number of around 10 traumatic ev ents throughout their lifespan, w ith boys being significantly more exposed than girls, as w ere those liv ing in v illages compared to Gaza city or refugee camp residents.Adolescents mainly and perv asiv ely reported objectiv e, nonpersonal material and media exposure.Around one -fifth also experienced direct, physical exposure and exposure through injury and death of relativ es.I n this context of intense continual exposure, more than half of the inv estigated adolescents liv ing in the Gaza Strip reported moderate to high lev els of posttraumatic stress symptoms, for one fifth among them this amounted to a probable posttraumatic stress disorder.
Remarkably, these PTSS lev els w ere not primarily linked to their differences in exposure lev els according to gender, place of residency and family income.
From a research perspectiv e, these findings suggest tw o major pathw ays for enhancing comprehension of middle to late Palestinian adolescents" posttraumatic stress reactions.First, it may be that the dose-response principle attains a ceilingeffect w hen adolescents attempt to adapt to lifelong exposure.Second, primary attributions and coping strategies may moderate adolescents" cognitiv e-emotional dynamics, leading to similar posttraumatic stress responses despite different lev els and types of exposure.From a practice perspectiv e, these findings underscore the perv asiv e need for prev ention and interv ention programs to help Palestinian adolescents deal w ith the substantiv e challenges of grow ing into adults in a context of prolonged indiv idual and collectiv e exposure to sociopolitical trauma.Last but not least, since around one tenth of the inv estigated adolescents reported relativ ely low lev els of posttraumatic stress, further identification of resiliency factors and dynamics is also strongly recommended.
Palestinian adolescents in the Gaza Strip 35 Despite these insights, the ev idence-base concerning adolescents" pathw ays w hen confronted w ith continual exposure to sociopolitical disputes remains limited to date.I n the first place, there is a clear need for empirical data as to w hich aspects of this exposure are determinant and under w hich circumstances.Ov erall prev alence of posttraumatic stress in Palestinian youth I n recent years, a number of studies hav e started to assess the lev els of PTSS or PTSD among Palestinian youth giv en their w idespread exposure to trauma.I ndeed, betw een September 2000 and Nov ember 2005, ov er 26000 Palest inians under the age of 18 years, representing about 7.5% of the child and adolescent population, w ere injured in the context of the Al-Aqsa I ntifada.Approximately 12% of the injured youngsters are now suffering from a permanent disability types of exposure to traumatic ev ents

Figure 1 :
Figure 1: Exposure to Traumatic Ev ents According to Gender

Figure 2 :
Figure 2: Exposure to Traumatic Ev ents According to Place of Residency

Table 1 .
Table 1 prov ides a complete ov erv iew of the sample"s family demographics.Percentage and Frequencies of Demographic Characteristics (N= 368)

Table 2 :
Types of Traumatic Ev ents experienced by Adolescents (N = 368)