In contrast to acute pain, chronic pain develops as a lasting disturba
nce of physiological control circuits because of (a) pathological symp
athetic and motor reflexes, (b) biochemically induced plastic changes
of the CNS with central learning phenomena and (c) psychologically as
reaction to the somatic disturbance or as a substitute for intrapsychi
c conflicts. Therefore the long-term treatment of chronic pain has to
be complex, taking into account not only the reduction of pain, but al
so physical functional restoration, psychological stabilisation and so
cial rehabilitation.