Depression is the leading cause of years lost due to disability worldwide. Still, the mechanisms underlying its development are not well understood. This study aimed to evaluate white-matter properties associated with depressive symptomatology in young adulthood and their developmental origins. Diffusion tensor imaging and assessment of depressive symptomatology were conducted in 128 young adults (47% male, age 23-24) from a prenatal birth cohort (European Longitudinal Study of Pregnancy and Childhood). For a subset of these individuals, the database included information on prenatal stress (n = 93) and depressive symptoms during adolescence (assessed repeatedly at age 15 and 19). Depressive symptoms in young adulthood were associated with lower fractional anisotropy in the left and right cingulum and higher fractional anisotropy in the right corticospinal tract and superior longitudinal fasciculus. Further analyses revealed that prenatal stress and depressive symptomatology during adolescence were independent predictors of altered white-matter properties in the cingulum in young adulthood. We conclude that typically developing young adults with more depressive symptoms already exhibit tract-specific alterations in white-matter properties and that prenatal stress and depressive symptomatology during adolescence might contribute to their development.

Brain and Mind Research Programme Central European Institute of Technology Masaryk University Brno Czech Republic

Child Mind Institute New York

Department of Neurology St Anne's University Hospital and Faculty of Medicine MU Brno Czech Republic

Departments of Psychology and Psychiatry University of Toronto Toronto Canada

Research Centre for Toxic Compounds in the Environment Faculty of Science Masaryk University Brno Czech Republic

Rotman Research Institute Baycrest Toronto Canada

Zobrazit více v PubMed

Antonow‐Schlorke, I. , Schwab, M. , Li, C. , & Nathanielsz, P. W. (2003). Glucocorticoid exposure at the dose used clinically alters cytoskeletal proteins and presynaptic terminals in the fetal baboon brain. The Journal of Physiology, 547(1), 117–123. PubMed PMC

Aung, W. Y. , Mar, S. , & Benzinger, T. L. S. (2013). Diffusion tensor MRI as a biomarker in axonal and myelin damage. Imaging in Medicine, 5(5), 427–440. PubMed PMC

Babri, S. , Doosti, M. H. , & Salari, A. A. (2014). Strain‐dependent effects of prenatal maternal immune activation on anxiety‐ and depression‐like behaviors in offspring. Brain, Behavior, and Immunity, 37, 164–176. PubMed

Beck, A. T. , Ward, C. H. , Mendelson, M. , Mock, J. , & Erbaugh, J. (1961). An inventory for measuring depression. Archives of General Psychiatry, 4, 561–571. PubMed

Betts, K. S. , Williams, G. M. , Najman, J. M. , & Alati, R. (2015). The relationship between maternal depressive, anxious, and stress symptoms during pregnancy and adult offspring behavioural and emotional problems. Depression and Anxiety, 32(2), 82–90. PubMed

Bilbo, S. D. , & Schwarz, J. M. (2009). Early‐life programming of later‐life brain and behavior: A critical role for the immune system. Frontiers in Behavioral Neuroscience, 3, 14. PubMed PMC

Blood, A. J. , Iosifescu, D. V. , Makris, N. , Perlis, R. H. , Kennedy, D. N. , & Dougherty, D. D. (2010). Phenotype genotype project on addiction and mood disorders: Microstructural abnormalities in subcortical reward circuitry of subjects with major depressive disorder. PLoS One, 5, e13945. PubMed PMC

Bock, J. , Rether, K. , Groger, N. , Xie, L. , & Braun, K. (2014). Perinatal programming of emotional brain circuits: An integrative view from systems to molecules. Frontiers in Neuroscience, 8, 11. PubMed PMC

Buss, C. , Davis, E. P. , Shahbaba, B. , Pruessner, J. C. , Head, K. , & Sandman, C. A. (2012a). Maternal cortisol over the course of pregnancy and subsequent child amygdala and hippocampus volumes and affective problems. Proceedings of the National Academy of Sciences of the United States of America, 109(20), E1312–E1319. PubMed PMC

Buss, C. , Davis, E. P. , Shahbaba, B. , Pruessner, J. C. , Head, K. , & Sandman, C. A. (2012b). Maternal cortisol over the course of pregnancy and subsequent child amygdala and hippocampus volumes and affective problems. Proceedings of the National Academy of Sciences of the United States of America, 109, E1312–E1319. PubMed PMC

Chen, G. , Guo, Y. , Zhu, H. , Kuang, W. , Bi, F. , Ai, H. , … Gong, Q. (2017). Intrinsic disruption of white matter microarchitecture in first‐episode, drug‐naive major depressive disorder: A voxel‐based meta‐analysis of diffusion tensor imaging. Progress in Neuro‐Psychopharmacology & Biological Psychiatry, 76, 179–187. PubMed

Chen, G. , Hu, X. , Li, L. , Huang, X. , Lui, S. , Kuang, W. , … Gong, Q. (2016). Disorganization of white matter architecture in major depressive disorder: A meta‐analysis of diffusion tensor imaging with tract‐based spatial statistics. Scientific Reports, 6, 21825. PubMed PMC

Choi, K. S. , Riva‐Posse, P. , Gross, R. E. , & Mayberg, H. S. (2015). Mapping the “depression switch”during intraoperative testing of subcallosal cingulated deep brain stimulation. JAMA Neurology, 72(11), 1252–1260. PubMed PMC

Coffey, C. E. , Figiel, G. S. , Djang, W. T. , Saunders, W. B. , & Weiner, R. D. (1989). White matter hyperintensity on magnetic resonance imaging: clinical and neuroanatomic correlates in the depressed elderly. The Journal of Neuropsychiatry and Clinical Neurosciences, 1(2), 135–144. PubMed

Coffey, C. E. , Wilkinson, W. E. , Weiner, R. D. , Parashos, I. A. , Djang, W. T. , Webb, M. C. , … Spritzer, C. E. (1993). Quantitative cerebral anatomy in depression: A controlled magnetic resonance imaging study. Archives of General Psychiatry, 50, 7–16. PubMed

Copeland, W. E. , Wolke, D. , Shanahan, L. , & Costello, E. J. (2015). Adult functional outcomes of common childhood psychiatric problems: A prospective, longitudinal study. JAMA Psychiatry, 72(9), 892–899. PubMed PMC

Davis, E. P. , Glynn, L. M. , Waffarn, F. , & Sandman, C. A. (2011). Prenatal maternal stress programs infant stress regulation. Journal of Child Psychology and Psychiatry, 52(2), 119–129. PubMed PMC

Davis, E. P. , & Sandman, C. A. (2012). Prenatal psychobiological predictors of anxiety risk in preadolescent children. Psychoneuroendocrinology, 37(8), 1224–1233. PubMed PMC

De Diego‐Adelino, J. , Pires, P. , Gómez‐Ansón, B. , Serra‐Blasco, M. , Vives‐Gilabert, Y. , Puigdemont, D. , … Portella, M. J. (2014). Microstructural white matter abnormalities associated with treatment resistance, severity and duration of illness in major depression. Psychological Medicine, 44(6), 1171–1182. PubMed

de Groot, J. C. , de Leeuw, F. E. , Oudkerk, M. , Hofman, A. , Jolles, J. , & Breteler, M. M. (2000). Cerebral white matter lesions and depressive symptoms in elderly adults. Archives of General Psychiatry, 57, 1071–1076. PubMed

Deoni, S. C. L. , Mercure, E. , Blasi, A. , Gasston, D. , Thomson, A. , Johnson, M. , … Murphy, D. G. M. (2011). Mapping infant brain myelination with magnetic resonance imaging. The Journal of Neuroscience, 31, 784–791. PubMed PMC

Enayati, M. , Solati, J. , Hosseini, M. H. , Shahi, H. R. , Saki, G. , & Salari, A. A. (2012). Maternal infection during late pregnancy increases anxiety‐ and depression‐like behaviors with increasing age in male offspring. Brain Research Bulletin, 87, 295–302. PubMed

Entringer, S. , Kumsta, R. , Hellhammer, D. H. , Wadhwa, P. D. , & Wust, S. (2009). Prenatal exposure to maternal psychosocial stress and HPA axis regulation in young adults. Hormones and Behavior, 55(2), 292–298. PubMed

Ghazi Sherbaf, F. , Same, K. , Ashraf‐Ganjouei, A. , & Aarabi, M. H. (2018). Altered white matter microstructure associated with mild and moderate depressive symptoms in young adults, a diffusion tensor imaging study. Neuroreport, 29(8), 685–689. 10.1097/WNR.0000000000001017 PubMed DOI

Giedd, J. (1999). Brain development, IX: Human brain growth. The American Journal of Psychiatry, 156, 4. PubMed

Golding, J. (1989). European longitudinal study of pregnancy and childhood (ELSPAC). Paediatric and Perinatal Epidemiology, 3(4), 460–469. PubMed

Goldstein, J. M. , Handa, R. J. , & Tobet, S. A. (2014). Disruption of fetal hormonal programming (prenatal stress) implicates shared risk for sex differences in depression and cardiovascular disease. Frontiers in Neuroendocrinology, 35, 140–158. PubMed PMC

Gunning‐Dixon, F. M. , Walton, M. , Cheng, J. , Acuna, J. , Klimstra, S. , Zimmerman, M. E. , … Alexopoulos, G. S. (2010). MRI signal hyperintensities and treatment remission of geriatric depression. Journal of Affective Disorders, 126, 395–401. PubMed PMC

Heilbronner, S. R. , & Haber, S. N. (2014a). Frontal cortical and subcortical projections provide a basis for segmenting the cingulum bundle: Implications for neuroimaging and psychiatric disorders. The Journal of Neuroscience, 34(30), 10041–10054. PubMed PMC

Heilbronner, S. R. , & Haber, S. N. (2014b). Frontal cortical and subcortical projections provide a basis for segmenting the cingulum bundle: Implications for neuroimaging and psychiatric disorders. The Journal of Neuroscience, 34(30), 10041–10054. PubMed PMC

Henderson, S. E. , Johnson, A. R. , Vallejo, A. I. , Katz, L. , Wong, E. , & Gabbay, V. (2013). A preliminary study of white matter in adolescent depression: Relationships with illness severity, anhedonia, and irritability. Frontiers in Psychiatry, 4, 152. PubMed PMC

Hoogenboom, W. S. , Perlis, R. H. , Smoller, J. W. , Zeng‐Treitler, Q. , Gainer, V. S. , Murphy, S. N. , … Iosifescu, D. V. (2014). Limbic system white matter microstructure and long‐term treatment outcome in major depressive disorder: A diffusion tensor imaging study using legacy data. The World Journal of Biological Psychiatry, 15, 122–134. PubMed PMC

Howard, R. J. , Beats, B. , Forstl, H. , Graves, P. , Bingham, J. , & Levy, R. (1993). White matter changes in late onset depression: A magnetic resonance imaging study. International Journal of Geriatric Psychiatry, 8, 183–185.

Huang, H. , Fan, X. , Williamson, D. E. , & Rao, U. (2011). White matter changes in healthy adolescents at familial risk for unipolar depression: A diffusion tensor imaging study. Neuropsychopharmacology, 36(3), 684–691. PubMed PMC

Huang, W. L. , Harper, C. G. , Evans, S. F. , Newnham, J. P. , & Dunlop, S. A. (2001). Repeated prenatal corticosteroid administration delays astrocyte and capillary tight junction maturation in fetal sheep. International Journal of Developmental Neuroscience, 19(5), 487–493. PubMed

Iosifescu, D. V. , Renshaw, P. F. , Lyoo, I. K. , Lee, H. K. , Perlis, R. H. , Papakostas, G. I. , … Fava, M. (2006). Brain white‐matter hyperintensities and treatment outcome in major depressive disorder. The British Journal of Psychiatry, 188, 180–185. PubMed

Jensen, S. K. G. , Pangelinan, M. , Björnholm, L. , Klasnja, A. , Leemans, A. , Drakesmith, M. , … Paus, T. (2017). Associations between prenatal, childhood, and adolescent stress and variations in white matter properties in young men. Neuroimage, 182, 389–397. 10.1016/j.neuroimage.2017.10.033 PubMed DOI PMC

Keedwell, P. A. , Chapman, R. , Christiansen, K. , Richardson, H. , Evans, J. , & Jones, D. K. (2012). Cingulum white matter in young women at risk of depression: The effect of family history and anhedonia. Biological Psychiatry, 72(4), 296–302. PubMed

Keedwell, P. A. , Doidge, A. N. , Meyer, M. , Lawrence, N. , Lawrence, A. D. , & Jones, D. K. (2016). Subgenual cingulum microstructure supports control of emotional conflict. Cerebral Cortex, 26(6), 2850–2862. PubMed PMC

Kendler, K. S. , Karkowski, L. M. , & Prescott, C. A. (1999). Causal relationship between stressful life events and the onset of major depression. Psychiatry: Interpersonal and Biological Processes, 156, 837–841. PubMed

Kessler, R. C. , Berglund, P. , Demler, O. , Jin, R. , Merikangas, K. R. , & Walters, E. E. (2005). Lifetime prevalence and age‐of‐onset distributions of DSM‐IV disorders in the National Comorbidity Survey Replication. Archives of General Psychiatry, 62(6), 593–602. PubMed

Khan, D. , Fernando, P. , Cicvaric, A. , Berger, A. , Pollak, A. , Monje, F. J. , & Pollak, D. D. (2014). Long‐term effects of maternal immune activation on depression‐like behaviour in the mouse. Translational Psychiatry, 4, e363. PubMed PMC

Kieseppa, T. , Eerola, M. , Mäntylä, R. , Neuvonen, T. , Poutanen, V. P. , Luoma, K. , … Isometsä, E. (2010). Major depressive disorder and white matter abnormalities: A diffusion tensor imaging study with tract‐based spatial statistics. Journal of Affective Disorders, 120, 240–244. PubMed

Konarski, J. Z. , McIntyre, R. S. , Kennedy, S. H. , Rafi–Tari, S. , Soczynska, J. K. , & Ketter, T. A. (2018). Volumetric neuroimaging investigations in mood disorders: Bipolar disorder versus major depressive disorder. Bipolar Disord, 10, 1–37. PubMed

Korgaonkar, M. S. , Grieve, S. M. , Koslow, S. H. , Gabrieli, J. D. , Gordon, E. , & Williams, L. M. (2011). Loss of white matter integrity in major depressive disorder: Evidence using tract‐based spatial statistical analysis of diffusion tensor imaging. Human Brain Mapping, 32(12), 2161–2171. PubMed PMC

Lebel, C. , Walker, L. , Leemans, A. , Phillips, L. , & Beaulieu, C. (2008). Microstructural maturation of the human brain from childhood to adulthood. NeuroImage, 40(3), 1044–1055. PubMed

Leemans, A. , & Jones, D. K. (2009). The B‐matrix must be rotated when correcting for subject motion in DTI data. Magnetic Resonance in Medicine, 61(6), 1336–1349. PubMed

Lemaire, V. , Koehl, M. , Le Moal, M. , & Abrous, D. N. (2000). Prenatal stress produces learning deficits associated with an inhibition of neurogenesis in the hippocampus. Proceedings of the National Academy of Sciences of the United States of America, 97(20), 11032–11037. PubMed PMC

Lemaire, V. , Lamarque, S. , Le Moal, M. , Piazza, P. V. , & Abrous, D. N. (2006). Postnatal stimulation of the pups counteracts prenatal stress‐induced deficits in hippocampal neurogenesis. Biological Psychiatry, 59(9), 786–792. PubMed

Lenze, E. , Cross, D. , McKeel, D. , Neuman, R. J. , & Sheline, Y. I. (1999). White matter hyperintensities and gray matter lesions in physically healthy depressed subjects. The American Journal of Psychiatry, 156(10), 1602–1607. PubMed

Liao, Y. , Huang, X. , Wu, Q. , Yang, C. , Kuang, W. , du, M. , … Gong, Q. (2013). Is depression a disconnection syndrome? Meta‐analysis of diffusion tensor imaging studies in patients with MDD. Journal of Psychiatry & Neuroscience, 38(1), 49–56. PubMed PMC

Lin, Y. L. , & Wang, S. (2014). Prenatal lipopolysaccharide exposure increases depression‐like behaviors and reduces hippocampal neurogenesis in adult rats. Behavioural Brain Research, 259, 24–34. PubMed

Ma, N. , Li, L. , Shu, N. , Liu, J. , Gong, G. , He, Z. , … Jiang, T. (2007). White matter abnormalities in first‐episode, treatment‐naive young adults with major depressive disorder. The American Journal of Psychiatry, 164, 823–826. PubMed

Mareckova, K. , Klasnja, A. , Bencurova, P. , Andryskova, L. , Brazdil, M. , & Paus, T. (2018). Prenatal stress, mood, and gray matter volume in young adulthood. Cerebral Cortex. 10.1093/cercor/bhy030 PubMed DOI PMC

Markham, J. A. , & Koenig, J. I. (2011). Prenatal stress: Role in psychotic and depressive diseases. Psychopharmacology, 214, 89–106. PubMed PMC

Moylan, S. , Maes, M. , Wray, N. R. , & Berk, M. (2013). The neuroprogressive nature of major depressive disorder: Pathways to disease evolution and resistance, and therapeutic implications. Molecular Psychiatry, 18(5), 595–606. PubMed

Murphy, M. L. , & Frodl, T. (2011). Meta‐analysis of diffusion tensor imaging studies shows altered fractional anisotropy occurring in distinct brain areas in association with depression. Biology of Mood & Anxiety Disorders, 1, 3. PubMed PMC

Park, S. , Kim, B. N. , Kim, J. W. , Shin, M. S. , Yoo, H. J. , Lee, J. , & Cho, S. C. (2014). Associations between maternal stress during pregnancy and offspring internalizing and externalizing problems in childhood. International Journal of Mental Health Systems, 8(1), 42–45. PubMed PMC

Paus, T. (2016). Chapter 2 – Population neuroscience In Handbook of clinical neurology. Elsevier, (Vol. 138, pp. 17–37). 10.1016/B978-0-12-802973-2.00002-1. PubMed DOI

Piler, P. , Kandrnal, V. , Kukla, L. , Andrýsková, L. , Švancara, J. , Jarkovský, J. , … Klánová, J. (2016). Cohort profile: European longitudinal study of pregnancy and childhood (ELSPAC) in the Czech Republic. International Journal of Epidemiology, 46(5), 1379–1379. PubMed PMC

Qiu, A. , Anh, T. T. , Li, Y. , Chen, H. , Rifkin‐Graboi, A. , Broekman, B. F. P. , … Meaney, M. J. (2015). Prenatal maternal depression alters amygdala functional connectivity in 6‐month‐old infants. Translational Psychiatry, 5, e508. PubMed PMC

Rabins, P. V. , Pearlson, G. D. , Aylward, E. , Kumar, A. J. , & Dowell, K. (1991). Cortical magnetic resonance imaging changes in elderly inpatients with major depression. The American Journal of Psychiatry, 148(5), 617–620. PubMed

Rifkin‐Graboi, A. , Meaney, M. J. , Chen, H. , Bai, J. , Hameed, W. B.’. , Tint, M. T. , … Qiu, A. (2015). Antenatal maternal anxiety predicts variations in neural structures implicated in anxiety disorders in newborns. Journal of the American Academy of Child and Adolescent Psychiatry, 54, 313–321. PubMed

Sandman, C. A. , Buss, C. , Head, K. , & Davis, E. P. (2015). Fetal exposure to maternal depressive symptoms is associated with cortical thickness in late childhood. Biological Psychiatry, 77, 324–334. PubMed PMC

Sarkar, S. , Craig, M. C. , Dell'Acqua, F. , O'Connor, T. G. , Catani, M. , Deeley, Q. , … Murphy, D. G. M. (2014). Prenatal stress and limbic‐prefrontal white matter microstructure in children aged 6‐9 years: A preliminary diffusion tensor imaging study. The World Journal of Biological Psychiatry, 15(4), 346–352. PubMed

Shimony, J. S. , Sheline, Y. I. , D'Angelo, G. , Epstein, A. A. , Benzinger, T. L. S. , Mintun, M. A. , … Snyder, A. Z. (2009). Diffuse microstructural abnormalities of normal‐appearing white matter in late life depression: A diffusion tensor imaging study. Biological Psychiatry, 66, 245–252. PubMed PMC

Szeszko, P. R. , Vogel, J. , Ashtari, M. , Malhotra, A. K. , Bates, J. , Kane, J. M. , … Lim, K. (2003). Sex differences in frontal lobe white matter microstructure: A DTI study. Neuroreport, 14, 2469–2473. PubMed

Tax, C. M. W. , Otte, W. M. , Viergever, M. A. , Dijkhuizen, R. M. , & Leemans, A. (2015). REKINDLE: Robust extraction of kurtosis INDices with linear estimation. Magnetic Resonance in Medicine, 73(2), 794–808. PubMed

Taylor, W. D. , Payne, M. E. , Krishnan, K. R. R. , Wagner, H. R. , Provenzale, J. M. , Steffens, D. C. , & MacFall, J. R. (2001). Evidence of white matter tract disruption in MRI hyperintensities. Biological Psychiatry, 50, 179–183. PubMed

UNICEF . (2017). The adolescent brain: A second window of opportunity. UNICEF Office of Research–Innocenti, Florence, Italy. Retrieved from https://www.unicef-irc.org/publications/pdf/adolescent_brain_a_second_window_of_opportunity_a_compendium.pdf

Ustun, T. B. , Ayuso‐Mateos, J. L. , Chatterji, S. , Mathers, C. , & Murray, C. J. L. (2004). Global burden of depressive disorders in the year 2000. British Journal of Psychiatry, 184, 386–392. PubMed

Van den Hove, D. L. A. , Steinbusch, H. W. , Scheepens, A. , Van de Berg, W. D. , Kooiman, L. A. , Boosten, B. J. , … Blanco, C. E. (2006). Prenatal stress and neonatal rat brain development. Neuroscience, 137(1), 145–155. PubMed

Veraart, J. , Sijbers, J. , Sunaert, S. , Leemans, A. , & Jeurissen, B. (2013). Weighted linear least squares estimation of diffusion MRI parameters: Strengths, limitations, and pitfalls. NeuroImage, 81, 335–346. PubMed

Wakana, S. , Caprihan, A. , Panzenboeck, M. M. , Fallon, J. H. , Perry, M. , Gollub, R. L. , … Mori, S. (2007). Reproducibility of quantitative tractography methods applied to cerebral white matter. NeuroImage, 36(3), 630–644. PubMed PMC

Walker, A. K. , Nakamura, T. , & Hodgson, D. M. (2010). Neonatal lipopolysaccha‐ ride exposure alters central cytokine responses to stress in adulthood in Wistar rats. Stress, 13(6), 506–515. PubMed

Weinstock, M. (2008). The long‐term behavioural consequences of prenatal stress. Neuroscience and Biobehavioral Reviews, 32, 1073–1086. PubMed

Wiggins, R. C. , & Gottesfeld, Z. (1986). Restraint stress during late pregnancy in rats elicits early hypermyelination in the offspring. Metabolic Brain Disease, 1, 197–203. PubMed

Wu, F. , Tang, Y. , Xu, K. , Kong, L. , Sun, W. , & Wang, F. (2011). White matter abnormalities in medication‐naive subjects with a single short duration episode of major depressive disorder. Psychiatry Research, 191, 80–83. PubMed PMC

Yong Ping, E. , Laplante, D. P. , Elgbeili, G. , Hillerer, K. M. , Brunet, A. , O'Hara, M. W. , & King, S. (2015). Prenatal maternal stress predicts stress reactivity at 2.5 years of age: The Iowa flood study. Psychoneuroendocrinology, 56, 62–78. PubMed

Zhu, X. , Wang, X. , Xiao, J. , Zhong, M. , Liao, J. , & Yao, S. (2011). Altered white matter integrity in first‐episode, treatment‐naive young adults with major depressive disorder: A tract‐based spatial statistics study. Brain Research, 1369, 223–229. PubMed

Zou, K. , Huang, X. , Li, T. , Gong, Q. , Li, Z. , Ou‐yang, L. , … Sun, X. (2008). Alterations of white matter integrity in adults with major depressive disorder: A magnetic resonance imaging study. Journal of Psychiatry & Neuroscience, 33(6), 525–530. PubMed PMC

Zubenko, G. S. , Sullivan, P. , Nelson, J. P. , Belle, S. H. , Huff, F. J. , & Wolf, G. L. (1990). Brain imaging abnormalities in mental disorders of late life. Archives of Neurology, 47(10), 1107–1111. PubMed

Parental education, cognition and functional connectivity of the salience network

Association of Maternal Depression During Pregnancy and Recent Stress With Brain Age Among Adult Offspring

Socioeconomic deprivation in early life and symptoms of depression and anxiety in young adulthood: mediating role of hippocampal connectivity

Socioeconomic and cognitive roots of trait anxiety in young adults

Temporally and sex-specific effects of maternal perinatal stress on offspring cortical gyrification and mood in young adulthood