ABSTRACT
The measurement of central nervous system (CNS) effects is particularly relevant for a new drug, not only when this drug is supposed to exert a psychotropic effect, but also for drugs acting on other systems for which possible side-effects or adverse reactions at the level of the CNS need to be investigated and assessed at the earliest stage of development. Clinical observation and follow-up of subjects administered with a new drug in Phase I and early Phase II will provide very superficial information on the appearance of manifestations such as sedation, drowsiness, sleepiness, excitation, irritability, insomnia, etc. More in-depth assessment of CNS effects demands the use of more structured and objective techniques. CNS effects can be classified, for practical and descriptive reasons, in terms of effects on behaviour, on vigilance/attention and cognition, on neurophysiological activity of the brain and on neuroendocrinological functions.
