This thesis deals with side effects of medicinal drugs on behaviour from a pharmacopsychological perspective. Because it focuses on behaviour and not on the drug itself, a much more refined study of the behavioural effects can be made and evaluated within an existing psychological theory or (neuro)psychological framework. Aided by the expanding knowledge of neurotransmitter systems and using new neuroimaging techniques, models have been developed linking biological functioning with overt behaviour. The thesis describes a series of eight experimental studies that investigate the feasibility of this approach in two distinct but specific behavioural domains: motor and cognitive performance. Motor performance in these studies is operationalised in terms of car driving in a specially instrumented vehicle. Before the presentation of the studies a number of psychological performance models are presented and their value for applied pharmacopsychology is discussed. As for the driving studies a development is described in which driving behaviour is placed in a broader context and not restricted to 'performance'. Models of behaviour that describe the role of risk taking and risk perception are likely to make a significant contribution to unravelling the complex behaviour of driving an automobile and the unwanted side effects on it caused by psychoactive drugs. Some possible flaws in the 'over the road' driving test are discussed and possible solutions to overcome them are proposed. More specifically, the idea of letting the driver exert more executive control during the test is presented as a target for future development of the field.
Samenvatting