Psychopathology, the science of mental dysfunctions, can and should be
based on (cognitive) neuroscience. In particular, concepts such as ne
uronal activation, neuroplasticity, and neuronal death can be used to
understand, and to treat, mental dysfunctions. Some of the basic princ
iples are illustrated using recent examples, such as the plasticity of
the serotonin system of the crab caused by a single social interactio
n, the 'psychotherapy' of specific language impairment and the effects
of stress on the hippocampus in human beings.