Why do many psychiatric disorders emerge during adolescence?


The peak age of onset for many psychiatric disorders is adolescence, a time of remarkable physical and behavioural changes. The processes in the brain that underlie these behavioural changes have been the subject of recent investigations. What do we know about the maturation of the human brain during adolescence? Do structural changes in the cerebral cortex reflect synaptic pruning? Are increases in white-matter volume driven by myelination? Is the adolescent brain more or less sensitive to reward? Finding answers to these questions might enable us to further our understanding of mental health during adolescence.

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Figure 1: Schematic representations of developmental trajectories in local volume of cortical grey matter, glucose metabolism and synaptic density.
Figure 2: Sexual dimorphism in the maturation of white matter during adolescence.
Figure 3: Functional connectivity correlates with resistance to peer influence.
Figure 4: Ranges of onset age for common psychiatric disorders.


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The authors' work is supported by the Canadian Institutes of Health Research (T.P.), the Royal Society, UK (T.P.) and the US National Institutes of Health (T.P., K.M. and J.N.G.).

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Correspondence to Tomáš Paus or Jay N. Giedd.

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Androgen insensitivity syndrome

(Also known as androgen resistance syndrome or testicular feminization.) An X-linked, recessive condition characterized by a complete or partial failure of virilization that is due to a mutation on the gene that encodes the androgen receptor.

Anti-saccade task

A task in which subjects are required to suppress the automatic response of making a saccade towards a target and, instead, produce an eye movement in the opposite direction.

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Diffusion tensor imaging

(DTI). An MRI-based technique that allows one to characterize the structural properties of white matter.

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(FA). The directionality of the (fast) diffusion of water in the extracellular space around the axons (in most common acquisition protocols). The more unidirectional the water diffusion is in a given fibre tract, the higher the FA value in that location.

Go/no-go task

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(MTR). A measure used for assessing white-matter properties; it provides information on the macromolecular content and structure of the tissue. Given that the macromolecules of myelin are the dominant source of MT signal in white matter, one can use MTR as an index of myelination. Note, however, that myelin is not likely to be the sole factor influencing the MTR.

Neural Darwinism

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Stop task

A test of response inhibition. On each trial, a stimulus (for example, a leftward- or rightward-pointing arrow) is displayed on a screen, and the subject has to respond as soon as possible by pressing the corresponding (left or right) key, unless a second stimulus (for example, a sound) signals that the response has to be withheld.

Stroop task

A task in which the subject is asked to name the colour of ink in which a word is displayed. The task is easy when the ink colour is congruent with the printed word (for example, 'red' printed in red ink). The task becomes difficult when the ink colour is incongruent with the printed word (for example, 'red' printed in green ink).

STS network

A set of regions, located along the superior temporal sulcus, that are involved in processing biological motion induced by the movement of different body parts, such as the eyes, the face or the entire body.

Tanner stage III

One of the five stages of puberty. Without resorting to a physical exam, pubertal stages can be assessed using, for example, the Puberty Development Scale, which is an eight-item self-report measure of physical development based on the Tanner stages with separate forms for males and females. For this scale there are five categories of pubertal status: prepubertal, beginning pubertal, midpubertal, advanced pubertal and postpubertal.


(Klinefelter's syndrome). A genetic syndrome that affects males and is caused by the presence of two X chromosomes (resulting in a 47-chromosome karotype).

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Paus, T., Keshavan, M. & Giedd, J. Why do many psychiatric disorders emerge during adolescence?. Nat Rev Neurosci 9, 947–957 (2008). https://doi.org/10.1038/nrn2513

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