The study of the biological determinants of abnormal behavior is not anymore psychiatry's stepchild, but a respected branch of that discipline. There is every reason to be optimistic over the future of biological psychiatry. The brain sciences are developing with astounding speed and the systematic attention for psychiatric-diagnosis and differential diagnosis renders biological psychiatry an unprecedented vitality.

One should, however, not ignore some disquieting prospects. The following points of concern are discussed: the alarming shortage of young research psychiatrists; the deficiencies in the teaching of biological psychiatry; the hesitancy to utilize the fruits of brain and behavior research in clinical practice; the shortcomings in psychiatric diagnosing; nosological tunnel vision and, finally, the danger of overrating biological psychiatry with the inevitable disappointment reaction that will follow. The scientific maturation of psychiatry is contingent on a balanced development of its constituents.

Schizophrenia is a neurobiological developmental disorder of basic neuro-integrative functions, resulting in failures of cognitive selfregulation. Neurophysiological and psychophysiological dysfunctions should be considered in connection with the ubiquitous cognitive dysfunctions. Schizophrenic patients have problems with the integration of information, resulting in deficits of perceptual organization, and in ‘metacognitive’ deficits of executive functions in the area of behavior and experience. The biological basis of these cognitive functions is in the frontal cortex, but the primary dysfunction seems to be a subcortical one. Negative symptoms can be understood as a secondary exhaustion mechanism, and partly as an adaptive process, corresponding with energetic deficits in information processing. Psychophysiological studies of regional cerebral blood flow, positron emission tomography, electrophysiological recordings and measures of eye tracking point to frontal dysfunction and hypoactivation in patients with negative symptoms. This agrees well with the results of cognitive studies. Psychophysiologists and cognitive psychologists are studying different aspects of the same systems disorder.

A vigilance state is characterized by a particular activity state of the motorIautonomic and psychiclcognitive functional systems. S-W screening is possible through poly graphic monitoring of physiological variables and signals. Quantification of these signals introduces a set of parameters allowing the characterisation of the sleep (dys)function. There is no consensus regarding the choice or definition of these parameters. A particular cluster is presented and their informative value with respect to clinical practice and research is discussed.