Aus der Einleitung: "Retrospektive Befragungsmethoden zur Erfassung sozialer Situationen und sozialer Ereignisse spielen in der entwicklungspsychologischen, der klinischpsychologischen und psychiatrischen Verlaufsforschung trotz ihrer immanenten Methodenschwächen eine bedeutende Rolle. Ihre Nachteile liegen bei der Erfassung längerer Zeitabschnitte in konkreten Erinnerungsmängeln, Deutungsversuchen und dem Bemühen vieler Personen, retrospektiv Kausalverbindung herzustellen. Aufgrund forschungspraktischer Probleme und ihrer größeren Ökonomie lassen sich jedoch in vielen, vor allem hypothesengenierenden Studien retrospektive Untersuchungsansätze nicht durch prospektive Verlaufsstudien ersetzen. Dies gilt sowohl für die Erfassung der "natürlichen", nicht systematisch/ experimentell beeinflußten Krankheitsverläufe bestimmter Patientengruppen, als auch für epidemiologisch-orientierte Langzeituntersuchung unbehandelter Fälle und gesunder Kontrollpersonen (Blohmke 1975, v. Cranach und Wittcxhen 1980). [...]"

This paper presents the findings of two independent studies which examined the test-retest reliability and the fall-off effects of the Munich Life Event List (MEL). The MEL is a three-step interview procedure for assessing life incidents which focusses on recognition processes rather than free recall. In a reliability study, test–retest coefficients of the MEL, based on a sample of 42 subjects, were quite stable over a 6-week interval. Stability for severe incidents appeared to be higher than for the less severe ones. In the fall-off study, a total rate of 30% fall-off was noted for all incidents reported retrospectively over an 8-year period. A more detailed analysis revealed average monthly fall-off effects of 0.36%. The size of fall-off effects was higher for non-severe and positive incidents than for severe incidents. This was particularly evident for the symptomatic groups. Non-symptomatic males reported a higheroverall number of life incidents than females. This was partly due to more frequent reporting of severe incidents. The findings of the fall-off study do not support the common belief that the reliability oflife incident report is much worse when the assessment period is extended over a period of several years as compared to the traditional 6-month period.

Aus der Einleitung: "Retrospektive Befragungsmethoden zur Erfassung sozialer Situationen und sozialer Ereignisse spielen in der entwicklungspsychologischen, der klinischpsychologischen und psychiatrischen Verlaufsforschung trotz ihrer immanenten Methodenschwächen eine bedeutende Rolle. Ihre Nachteile liegen bei der Erfassung längerer Zeitabschnitte in konkreten Erinnerungsmängeln, Deutungsversuchen und dem Bemühen vieler Personen, retrospektiv Kausalverbindung herzustellen. Aufgrund forschungspraktischer Probleme und ihrer größeren Ökonomie lassen sich jedoch in vielen, vor allem hypothesengenierenden Studien retrospektive Untersuchungsansätze nicht durch prospektive Verlaufsstudien ersetzen. Dies gilt sowohl für die Erfassung der "natürlichen", nicht systematisch/ experimentell beeinflußten Krankheitsverläufe bestimmter Patientengruppen, als auch für epidemiologisch-orientierte Langzeituntersuchung unbehandelter Fälle und gesunder Kontrollpersonen (Blohmke 1975, v. Cranach und Wittcxhen 1980). [...]"

The 5-HTT gene (SLC6A4) is regulated by a common polymorphism in the promoter region (5-HTTLPR), which has functional consequences. Two major alleles have been observed and shown to have differential transcriptional activity with the long (L) allele having greater gene expression than the short (S) allele. 5-HTTLPR appears to modulate depression, anxiety and personality traits such as neuroticism. Additionally, a significant influence of 5-HTTLPR genotype on amygdala reactivity in response to fearful stimuli has been reported. Moreover, 5-HTTLPR seems to impact on the role of stressful life events (SLEs) in the development of depression. An elevated risk of depression and suicidal behaviors has been found in carriers of at least one low expressing S allele who had experienced SLEs, suggesting a gene x environment interaction. However, a recent meta-analysis showed that several findings failed to replicate this finding. Since genetic polymorphisms of the dopaminergic and serotonergic neurotransmission interact at the molecular, analyses with another polymorphism of the dopaminergic system, the dopamine D4 receptor (DRD4) was included to consider these likely gene-gene interactions (epistasis). The aim of this series of studies was to investigate the role 5-HTTLPR and SLEs on the endocrine stress response in different age samples. While newborns have been examined by a heel prick, stress responses were provoked in children (8-12 yrs) and younger adults (19-31 yrs) and older adults (54-68 yrs.) with the Trier Social Stress Test (TSST). The Life History Calendar (LHC) and Life Events Questionnaire (LEQ) were used to acquire data on SLEs. While in newborns the S/S genotype showed a significantly higher acute endocrine stress response than L/L or S/L genotypes, no significant difference between genotype groups was found in children. In the younger adult sample, the genotype impacted on cortisol stress responsiveness was reversed. Adults carrying the more active L allele of the 5-HTTLPR polymorphism showed a significantly larger cortisol response to the TSST than individuals carrying at least one of the lower expressing S allele. In older adults, no significant difference between genotype groups was found. However, results point in the same direction with showing highest cortisol response in individuals with L/L genotype. These data suggest that the association between 5-HTTLPR and endocrine stress reactivity seems to alter across lifespan, more specific the effects of genotype turns around. In addition, a significant interaction effect of 5-HTTLPR and SLEs has been found in the sample of younger adults, i.e. that early SLE as well as a severe number SLEs across the entire lifespan seem to modulate the interaction between HPA axis activity and 5-HTTLPR genotype. Additionally, a DRD4 by 5-HTTLPR interaction emerged which point to independent and joint effects of these polymorphisms on stress responsivity with regard to the concept of genegene interaction.

Background. There are inconclusive findings regarding whether danger and loss events differentially predict the onset of anxiety and depression. Method. A community sample of adolescents and young adults (n=2304, age 14–24 years at baseline) was prospectively followed up in up to four assessments over 10 years. Incident anxiety and depressive disorders were assessed at each wave using the DSM-IV/M-CIDI. Life events (including danger, loss and respectively mixed events) were assessed at baseline using the Munich Event List (MEL). Logistic regressions were used to reveal associations between event types at baseline and incident disorders at follow-up. Results. Loss events merely predicted incident ‘pure’ depression [odds ratio (OR) 2.4 per standard deviation, 95% confidence interval (CI) 1.5–3.9, p<0.001] whereas danger events predicted incident ‘pure’ anxiety (OR 2.3, 95% CI 1.1–4.6, p=0.023) and ‘pure’ depression (OR 2.5, 95% CI 1.7–3.5, p<0.001). Mixed events predicted incident ‘pure’ anxiety (OR 2.9, 95% CI 1.5–5.7, p=0.002), ‘pure’ depression (OR 2.4, 95% CI 1.6–3.4, p<0.001) and their co-morbidity (OR 3.6, 95% CI 1.8–7.0, p<0.001). Conclusions. Our results provide further evidence for differential effects of danger, loss and respectively mixed events on incident anxiety, depression and their co-morbidity. Since most loss events referred to death/separation from significant others, particularly interpersonal loss appears to be highly specific in predicting depression.

Aims. To prospectively examine whether negative life events (NLE) and low perceived coping efficacy (CE) increase the risk for the onset of various forms of psychopathology and low CE mediates the associations between NLE and incident mental disorders. Methods. A representative community sample of adolescents and young adults (N = 3017, aged 14–24 at baseline) was prospectively followed up in up to three assessment waves over 10 years. Anxiety, depressive and substance use disorders were assessed at each wave using the DSM-IV/M-CIDI. NLE and CE were assessed at baseline with the Munich Event List and the Scale for Self-Control and Coping Skills. Associations (odds ratios, OR) of NLE and CE at baseline with incident mental disorders at follow-up were estimated using logistic regressions adjusted for sex and age. Results. NLE at baseline predicted the onset of any disorder, any anxiety disorder, panic disorder, agoraphobia, generalised anxiety disorder, any depression, major depressive episodes, dysthymia, any substance use disorder, nicotine dependence and abuse/dependence of illicit drugs at follow-up (OR 1.02–1.09 per one NLE more). When adjusting for any other lifetime disorder prior to baseline, merely the associations of NLE with any anxiety disorder, any depression, major depressive episodes, dysthymia and any substance use disorder remained significant (OR 1.02–1.07). Low CE at baseline predicted the onset of any disorder, any anxiety disorder, agoraphobia, generalised anxiety disorder, any depression, major depressive episodes, dysthymia, any substance use disorder, alcohol abuse/dependence, nicotine dependence and abuse/dependence of illicit drugs at follow-up (OR 1.16–1.72 per standard deviation). When adjusting for any other lifetime disorder prior to baseline, only the associations of low CE with any depression, major depressive episodes, dysthymia, any substance use disorder, alcohol abuse/dependence, nicotine dependence and abuse/dependence of illicit drugs remained significant (OR 1.15–1.64). Low CE explained 9.46, 13.39, 12.65 and 17.31% of the associations between NLE and any disorder, any depression, major depressive episodes and dysthymia, respectively. When adjusting for any other lifetime disorder prior to baseline, the reductions in associations for any depression (9.77%) and major depressive episodes (9.40%) remained significant, while the reduction in association for dysthymia was attenuated to non-significance ( p-value > 0.05). Conclusions. Our findings suggest that NLE and low perceived CE elevate the risk for various incident mental disorders and that low CE partially mediates the association between NLE and incident depression. Subjects with NLE might thus profit from targeted early interventions strengthening CE to prevent the onset of depression.

This paper presents the findings of two independent studies which examined the test-retest reliability and the fall-off effects of the Munich Life Event List (MEL). The MEL is a three-step interview procedure for assessing life incidents which focusses on recognition processes rather than free recall. In a reliability study, test–retest coefficients of the MEL, based on a sample of 42 subjects, were quite stable over a 6-week interval. Stability for severe incidents appeared to be higher than for the less severe ones. In the fall-off study, a total rate of 30% fall-off was noted for all incidents reported retrospectively over an 8-year period. A more detailed analysis revealed average monthly fall-off effects of 0.36%. The size of fall-off effects was higher for non-severe and positive incidents than for severe incidents. This was particularly evident for the symptomatic groups. Non-symptomatic males reported a higheroverall number of life incidents than females. This was partly due to more frequent reporting of severe incidents. The findings of the fall-off study do not support the common belief that the reliability oflife incident report is much worse when the assessment period is extended over a period of several years as compared to the traditional 6-month period.

Background: Early negative life events (NLE) have long-lasting influences on neurodevelopment and psychopathology. Reduced orbitofrontal cortex (OFC) thickness was frequently associated with NLE and depressive symptoms. OFC thinning might mediate the effect of NLE on depressive symptoms, although few longitudinal studies exist. Using a complete longitudinal design with four time points, we examined whether NLE during childhood and early adolescence predict depressive symptoms in young adulthood through accelerated OFC thinning across adolescence. Methods: We acquired structural MRI from 321 participants at two sites across four time points from ages 14 to 22. We measured NLE with the Life Events Questionnaire at the first time point and depressive symptoms with the Center for Epidemiologic Studies Depression Scale at the fourth time point. Modeling latent growth curves, we tested whether OFC thinning mediates the effect of NLE on depressive symptoms. Results: A higher burden of NLE, a thicker OFC at the age of 14, and an accelerated OFC thinning across adolescence predicted young adults' depressive symptoms. We did not identify an effect of NLE on OFC thickness nor OFC thickness mediating effects of NLE on depressive symptoms. Conclusions: Using a complete longitudinal design with four waves, we show that NLE in childhood and early adolescence predict depressive symptoms in the long term. Results indicate that an accelerated OFC thinning may precede depressive symptoms. Assessment of early additionally to acute NLEs and neurodevelopment may be warranted in clinical settings to identify risk factors for depression.

Decades of research in quantitative genetics have found substantial heritability for personality traits as well as for mental disorders which formed the basis of the ongoing molecular genetic studies that aim to identify genetic variations that actually contribute to the manifestation of complex traits. With regard to psychological traits, genetic variation impacting neurotransmitter function have been of particular interest. Additionally, the role of environmental factors including gene × environment interactions has been further investigated and the impor-tance of developmental aspects has been stressed. Furthermore, endophenotypes which link complex traits with their respective biological underpinnings and thus bridge the gap between gene and behaviour have begun to be included in research efforts. In accordance with this approach, this thesis aims to further examine the influence of genetic variation impacting serotonergic and dopaminergic functioning on endophenotypes of anxiety-related behaviour. To this end, two well established paradigms – the acoustic startle reflex and the cortisol stress response – were employed. Both show considerable interindividual variation which has been found in quantitative genetic studies to be at least partly based on genetic factors. In addition, the neural circuits underlying these endophenotypes are relatively well understood and thus reveal references for the detection of associated genetic influences. The results of this thesis associate the overall startle magnitude in two independent samples of young adults with a polymorphism in the promoter region of the serotonin transporter (5-HTT) gene (5-HTTLPR): Carriers of the short (S) allele which results in a reduced gene ex-pression showed a stronger startle magnitude which is in line with numerous findings linking the S allele to increased measures of negative emotionality. In addition to 5-HTTLPR, the effects of past stressful life events on the startle response were investigated: Participants who had recently experienced at least one stressful life event exhibited stronger startle responses and reduced habituation of the startle reflex although there was no 5-HTTLPR × environment inter-action effect. A third study revealed independent and joint effects of 5-HTTLPR and a poly-morphism in the dopamine receptor 4 gene (DRD4) in the same sample of young adults with regard to the cortisol stress response with carriers of the DRD4 7R allele which has been associ-ated with higher scores in sensation seeking, showing reduced cortisol responses. In addition, a 5-HTTLPR × DRD4 interaction effect emerged: 5-HTTLPR long (L) allele carriers showed the lowest cortisol response but only when they possessed at least one copy of the DRD4 7R allele. Moreover, in a fourth study a life span approach was taken and the influence of a further important serotonergic polymorphism which impacts the functioning of tryptophan hydroxylase 2 (TPH2), the rate limiting enzyme in the biosynthesis of serotonin, on interindividual differences in the startle response was investigated in three different age samples: children, young adults and older adults. There was a sex × TPH2 genotype interaction effect in a sample of young adults on the overall startle response while there was no effect of TPH2 in children or older adults. The last study of this thesis presents findings regarding the influence of two dopaminergic polymorphisms in genes encoding the enzyme catechol-O-methyltransferase (COMT) and the dopamine transporter (DAT), respectively, which both terminate dopamine signalling and are thus important regulators of dopaminergic neurotransmission, on the startle reflex in older adults. COMT met/met homozygotes showed the strongest and val/val homozygotes displayed the smallest startle magnitude which is in line with findings linking the COMT met allele to increased scores of anxiety related traits and disorders. Regarding DAT, participants homozygous for the 10R allele, which had previously associated with attention-deficit hyperactivity disorder, showed a stronger overall startle response. In sum, this thesis comprises data on interindividual differences in an electrophysiological and a hormonal endophenotype across the life span and their association with serotonergic and dopaminergic function based on genetic variation. One major finding is the clear evidence for the influence of serotonergic polymorphisms on the startle response in young adults while in contrast in older adults genetic variation in the dopaminergic system exerted considerable influence. These differences might be due to developmental processes in the different stages of life although cohort effects and effects of different recruitment strategies can also not be ruled out. Furthermore, there were significant differences regarding the genetic influence on the acoustic startle reflex and cortisol stress response in one and the same sample which might be due to methodological differences of the two paradigms as well as differences in their underlying neuronal circuits. In conclusion, this thesis supports the acoustic startle reflex and the cortisol stress response as valuable endophenotypes and thus indicators for underlying neurobiological circuits although some methodological issues remain. It also highlights the importance of taking developmental factors and changes over the course of life into account. Finally, this thesis emphasizes the necessity to include reliably and validly assessed past experienced events in molecular genetic studies in order to understand the interplay between genetic and environmental factors in shaping (endo)-phenotypes.

Decades of research in quantitative genetics have found substantial heritability for personality traits as well as for mental disorders which formed the basis of the ongoing molecular genetic studies that aim to identify genetic variations that actually contribute to the manifestation of complex traits. With regard to psychological traits, genetic variation impacting neurotransmitter function have been of particular interest. Additionally, the role of environmental factors including gene × environment interactions has been further investigated and the impor-tance of developmental aspects has been stressed. Furthermore, endophenotypes which link complex traits with their respective biological underpinnings and thus bridge the gap between gene and behaviour have begun to be included in research efforts. In accordance with this approach, this thesis aims to further examine the influence of genetic variation impacting serotonergic and dopaminergic functioning on endophenotypes of anxiety-related behaviour. To this end, two well established paradigms – the acoustic startle reflex and the cortisol stress response – were employed. Both show considerable interindividual variation which has been found in quantitative genetic studies to be at least partly based on genetic factors. In addition, the neural circuits underlying these endophenotypes are relatively well understood and thus reveal references for the detection of associated genetic influences. The results of this thesis associate the overall startle magnitude in two independent samples of young adults with a polymorphism in the promoter region of the serotonin transporter (5-HTT) gene (5-HTTLPR): Carriers of the short (S) allele which results in a reduced gene ex-pression showed a stronger startle magnitude which is in line with numerous findings linking the S allele to increased measures of negative emotionality. In addition to 5-HTTLPR, the effects of past stressful life events on the startle response were investigated: Participants who had recently experienced at least one stressful life event exhibited stronger startle responses and reduced habituation of the startle reflex although there was no 5-HTTLPR × environment inter-action effect. A third study revealed independent and joint effects of 5-HTTLPR and a poly-morphism in the dopamine receptor 4 gene (DRD4) in the same sample of young adults with regard to the cortisol stress response with carriers of the DRD4 7R allele which has been associ-ated with higher scores in sensation seeking, showing reduced cortisol responses. In addition, a 5-HTTLPR × DRD4 interaction effect emerged: 5-HTTLPR long (L) allele carriers showed the lowest cortisol response but only when they possessed at least one copy of the DRD4 7R allele. Moreover, in a fourth study a life span approach was taken and the influence of a further important serotonergic polymorphism which impacts the functioning of tryptophan hydroxylase 2 (TPH2), the rate limiting enzyme in the biosynthesis of serotonin, on interindividual differences in the startle response was investigated in three different age samples: children, young adults and older adults. There was a sex × TPH2 genotype interaction effect in a sample of young adults on the overall startle response while there was no effect of TPH2 in children or older adults. The last study of this thesis presents findings regarding the influence of two dopaminergic polymorphisms in genes encoding the enzyme catechol-O-methyltransferase (COMT) and the dopamine transporter (DAT), respectively, which both terminate dopamine signalling and are thus important regulators of dopaminergic neurotransmission, on the startle reflex in older adults. COMT met/met homozygotes showed the strongest and val/val homozygotes displayed the smallest startle magnitude which is in line with findings linking the COMT met allele to increased scores of anxiety related traits and disorders. Regarding DAT, participants homozygous for the 10R allele, which had previously associated with attention-deficit hyperactivity disorder, showed a stronger overall startle response. In sum, this thesis comprises data on interindividual differences in an electrophysiological and a hormonal endophenotype across the life span and their association with serotonergic and dopaminergic function based on genetic variation. One major finding is the clear evidence for the influence of serotonergic polymorphisms on the startle response in young adults while in contrast in older adults genetic variation in the dopaminergic system exerted considerable influence. These differences might be due to developmental processes in the different stages of life although cohort effects and effects of different recruitment strategies can also not be ruled out. Furthermore, there were significant differences regarding the genetic influence on the acoustic startle reflex and cortisol stress response in one and the same sample which might be due to methodological differences of the two paradigms as well as differences in their underlying neuronal circuits. In conclusion, this thesis supports the acoustic startle reflex and the cortisol stress response as valuable endophenotypes and thus indicators for underlying neurobiological circuits although some methodological issues remain. It also highlights the importance of taking developmental factors and changes over the course of life into account. Finally, this thesis emphasizes the necessity to include reliably and validly assessed past experienced events in molecular genetic studies in order to understand the interplay between genetic and environmental factors in shaping (endo)-phenotypes.