Three community groups were compared: resilient adolescents – with low risk of mental disorder despite high exposure to lifetime stress, adolescents at risk of mental disorder exposed to the same level of stress, and controls. Personality was assessed by NEO Five Factor Inventory (NEO-FFI) and cognitive function by a battery of tests. Voxelwise statistics of DTI values in CC were obtained using Tract-Based Spatial Statistic. Regional projections were identified by probabilistic tractography.

Higher FA values were detected in the anterior CC of resilient compared with both non-resilient and control adolescents. FA values varied according to resilience capacity. Regional changes in CC were in regions that project onto anterior cingulated and frontal cortex. Neuroticism and three other personality factors differentiated at risk adolescents from the other two groups.

High FA was detected in resilient adolescents in an anterior CC region projecting to frontal areas subserving cognitive resources. Psychiatric risk in adolescents was associated with personality characteristics. Resilience in adolescence may be a dimension embedding white matter features.

Differences in personality traits have long been acknowledged as potential risk factors in developing psychiatric disorders. Lately, several susceptibility genes of different psychiatric disorders have been linked to personality traits. This has not been done for schizophrenia yet. Neuregulin1 has been repeatedly shown to be associated with schizophrenia and is involved in numerous neurodevelopmental functions such as neuronal migration and myelination. The impact of this gene might also modulate personality traits in healthy subjects.

The NRG1 status of 523 healthy subjects was determined with a single nucleotide polymorphism (SNP8NRG221533) which has been described as a tagging marker being part of the core at-risk haplotype for schizophrenia. Genotype was correlated with personality traits using the NEO-FFI questionnaire.

Subjects with the NRG1 risk allele scored higher on neuroticism (p <.05) and lower on conscientiousness (p <.05). Further, interactions of genotype by gender for extraversion (p <.05), openness (p <.05) and conscientiousness (p <.05) were found with men carrying the risk allele scoring the lowest.

The data indicate that the NRG1 gene which has found to be associated with schizophrenia may also influence personality differences in healthy subjects.

Reports of changes in patients’ social behavior during deep brain stimulation (DBS) raised the question whether DBS induces changes in personality. This study explored if (1) DBS is associated with changes in personality in patients suffering from treatment-resistant depression (TRD), (2) how personality dimensions and depression are associated, and (3) if TRD patients’ self-ratings of personality are valid.

TRD patients were assessed before DBS (n = 30), 6 months (t2, n = 21), 2 (t3, n = 17) and 5 years (t4, n = 11) after the initiation of DBS of the supero-lateral branch of the medial forebrain bundle (slMFB-DBS). Personality was measured with the NEO-Five-Factor Inventory (NEO-FFI), depression severity with Hamilton (HDRS), and Montgomery–Åsberg Depression Rating Scale (MADRS).

Personality dimensions did not change with slMFB-DBS compared with baseline. Extraversion was negatively correlated with HDRS28 (r = −0.48, p < 0.05) and MADRS (r = −0.45, p < 0.05) at t2. Inter-rater reliability was high for the NEO-FFI at baseline (Cronbach's α = 0.74) and at t4 (α = 0.65). Extraversion [t(29) = −5.20; p < 0.001] and openness to experience [t(29) = −6.96; p < 0.001] differed statistically significant from the normative sample, and did not predict the antidepressant response.

slMFB-DBS was not associated with a change in personality. The severity of depression was associated with extraversion. Personality of TRD patients differed from the healthy population and did not change with response, indicating a possible scar effect. Self-ratings of personality seem valid to assess personality during TRD.

It is well recognized that an individual's personality characteristics influence their psychological adjustment after stroke. However, there is a lack of research on the reliability of personality inventories for stroke. This study primarily aimed to evaluate the reliability of the Neuroticism, Extroversion, Openness to Experience (NEO)-Five Factor Inventory (NEO-FFI) for assessing pre-morbid personality and personality changes after stroke. Further aims were to investigate changes in personality during the hospital-to-home transition period and examine associations between personality and mood.

Forty participants with stroke (52.5% male, M age=65.55 years) were recruited at time of hospital discharge and completed the NEO-FFI, Centre for Epidemiologic Studies – Depression and Geriatric Anxiety Inventory. Significant others completed an informant version of the NEO-FFI. Stroke participants were re-assessed on the NEO-FFI at 1-month and 4-months post-discharge. Forty matched controls also completed the NEO-FFI.

Internal consistency was adequate for the NEO-FFI (α=0.57–0.86), although low for agreeableness. There was fair to excellent concordance between self-rated and informant versions of the NEO-FFI (ICC=0.58–0.78). Significant positive associations were found between neuroticism and mood (r=0.50–0.68), and significant negative associations were found between extraversion and mood (r=−0.33–0.36) and agreeableness and anxiety (r=−0.43). Self-ratings of stroke participants on the NEO-FFI at discharge did not significantly differ from matched controls. Extraversion levels significantly decreased, and agreeableness levels significantly increased between discharge and 1- and 4-months post-discharge.

Overall, the results support the reliability of the NEO-FFI for assessing personality characteristics in the context of stroke.

Resilience is the capacity of individuals to resist mental disorders despite exposure to stress. Little is known about its neural underpinnings. The putative variation of white-matter microstructure with resilience in adolescence, a critical period for brain maturation and onset of high-prevalence mental disorders, has not been assessed by diffusion tensor imaging (DTI). Lower fractional anisotropy (FA) though, has been reported in the corpus callosum (CC), the brain's largest white-matter structure, in psychiatric and stress-related conditions. We hypothesized that higher FA in the CC would characterize stress-resilient adolescents.

Three groups of adolescents recruited from the community were compared: resilient with low risk of mental disorder despite high exposure to lifetime stress (n = 55), at-risk of mental disorder exposed to the same level of stress (n = 68), and controls (n = 123). Personality was assessed by the NEO-Five Factor Inventory (NEO-FFI). Voxelwise statistics of DTI values in CC were obtained using tract-based spatial statistics. Regional projections were identified by probabilistic tractography.

Higher FA values were detected in the anterior CC of resilient compared to both non-resilient and control adolescents. FA values varied according to resilience capacity. Seed regional changes in anterior CC projected onto anterior cingulate and frontal cortex. Neuroticism and three other NEO-FFI factor scores differentiated non-resilient participants from the other two groups.

High FA was detected in resilient adolescents in an anterior CC region projecting to frontal areas subserving cognitive resources. Psychiatric risk was associated with personality characteristics. Resilience in adolescence may be related to white-matter microstructure.

Some personality characteristics have previously been associated with an increased risk for psychiatric disorder. Longitudinal studies are required in order to tease apart temporary (state) and enduring (trait) differences in personality among individuals with bipolar disorder (BD). This study aimed to determine whether there is a characteristic personality profile in BD, and whether associations between BD and personality are best explained by state or trait effects.

A total of 2247 participants in the Systematic Treatment Enhancement Program for Bipolar Disorder study completed the NEO Five-Factor Inventory administered at study entry, and at 1 and 2 years.

Personality in BD was characterized by high neuroticism (N) and openness (O), and low agreeableness (A), conscientiousness (C) and extraversion (E). This profile was replicated in two independent samples, and openness was found to distinguish BD from major depressive disorder. Latent growth modeling demonstrated that manic symptoms were associated with increased E and decreased A, and depressed symptoms with higher N and lower E, A, C and O. During euthymic phases, high N and low E scores predicted a future depression-prone course.

While there are clear state effects of mood on self-reported personality, personality variables during euthymia predict future course of illness. Personality disturbances in extraversion, neuroticism and openness may be enduring characteristics of patients with BD.