Adolescent brain development and implications for mental health

Adolescence is a phase of many brain changes. Advances in brain imaging techniques, such as magnetic resonance imaging (MRI) and diffusion tensor imaging (DTI) have increased our knowledge about the changes in structure of the brain around this time, and functional MRI has improved our understanding of brain activity and the connections between different parts of the nervous system. Structural and functional developmental changes in adolescence are linked to behavioural, cognitive and emotional changes in adolescence. These interact with psychological and social factors to affect a young person’s social functioning and mental state. For example, we now know that synaptic pruning and white matter maturation occur in adolescence and young adulthood, and this leads to refinement and strengthening of neural circuits. This is linked with mature cognitive styles such as abstract reasoning and planning and improved coordination between emotion and cognition. The fact that the brain is still developing in adolescence helps us to understand the emotional dysregulation, reduced impulse control and risk-taking that is often seen in this phase. The adolescent brain is likely to support the challenges specific to that period of life, when novelty and reward-seeking and risk-taking might be adaptive in facilitating movement away from the family origin and towards increasing independence. Understanding normal and abnormal brain development around this time also helps to shed light on the onset of mental disorders.