Adolescence has fascinated developmental scholars because the transition into adolescence involves biological, psychological, and social changes (Graber & Brooks-Gunn, 1996). At the same time, adolescence has been a focus for research on psychopathology as rates of several disorders increase dramatically during this time period. Most notably, the past few decades have witnessed volumes of studies and theories on adolescent depression, conduct disorder, and subclinical psychopathology (Steinberg & Morris, 2001). Many of these studies have sought to understand the confluence of bio-psychosocial developmental factors that result in the emergence of serious behavioral and emotional problems. In this chapter, we consider several bio-psychosocial models that have been used to explain changes in internalizing and externalizing behaviors during adolescence. Examples from our own work highlight the role of pubertal development in understanding behavioral plasticity during adolescence.

Discussions of plasticity in developmental processes have frequently focused on early development and gene–environment interactions in understanding development and behavior (Baltes, Lindenberger, & Staudinger, 1998). Despite a focus on the early periods of development, the notion that adaptation occurs in neural and behavioral development throughout life has been a cornerstone of life span developmental perspectives (Baltes et al., 1998; Cairns, 1998). Recent studies in neuroscience have demonstrated that new neural connections continue to be made across the life span (e.g., Bruer & Greenough, 2001) and specific changes in the prefrontal cortex and limbic regions of the brain occur during adolescence (see Spear, 2000 for a review).