Background: Relative to other psychiatric disorders, patients with schizophrenia are often unaware of the consequences of their disease and their need for treatment. These deficits in awareness referred in general in the English literature as "poor insight", have been the focus of many clinical studies over recent years. This phenomenon, which is considered as fundamental in clinical evaluations of schizophrenia, should be understood as a multidimensional process rather than a dichotomic phenomenon, as is presently the case. The links between insight deficits and responses to vocational rehabilitation efforts represent a major interest in research, including those related to medication compliance and clinical outcome. To conduct such studies, various evaluation tools have been developed, enabling the assessment of insight, of its time-course and of its components in psychosis and schizophrenia spectrum disorders.
Literature findings: The Scale to Assess Unawareness of illness in Mental Disorders (SUMD) developed by Amador and Strauss appears to be the most frequently used scale for the evaluation of awareness of the disorder in schizophrenia. Although the model proposed by Amador and Strauss is considered as the privileged model in the multidimensional approach of insight, it corresponds only to a phenomenological analysis of this concept. In the second part of this article, we thus review the current models attempting to explain the lack of insight in schizophrenia. Four current explanatory models of lack of insight will be described as follows: resulting either from adaptation or defence mechanisms to environmental stressors, resulting from cognitive bias of data processing, resulting from neuropsychological functional deficits and resulting from metacognitive deficits.
Discussion: Several hypotheses concerning these deficits arise from clinical studies. Although coping, and defence mechanisms to the consequences and stigmatization of the disease were hardly studied, the fact that poor insight does not appear related to the severity of symptomatology or to the emotional state of the patients argue against this hypothesis. Conversely, a considerable body of literature emphasized how unawareness may result from cognitive deficits. Research in neuropsychology and cognitive psychology has provided consistent results concerning the link between deficit in executive functions, frontal lobe dysfunction and poor insight. Recent studies on bias in cognitive information treatment and social cognition theories currently open new prospects.