Described over 100 years ago, schizophrenia remains one of the most mysterious, severe and complex diseases in psychiatry today. It is characterised by a set of symptoms that persist over a period of several months. Three groups of clinical signs not necessarily present simultaneously in the same patient are identified: so-called “positive” symptoms which “add up” to ordinary perceptions: these are perceptions without an object called auditory, olfactory, gustatory, visual or coenesthetic hallucinations (a modification of body sensations), as well as delirious ideas of megalomania, persecution, transmission of thought, sometimes very bizarre…. Experienced as real, these symptoms are often very distressing and a source of considerable suffering which can endanger the person with so-called “negative” signs that are expressed by the reduction of all activity : people show an emotional attenuation (which can go as far as emotional indifference) and have difficulty in maintaining a social life; finally, a series of symptoms that reflect the disorganisation of thought and behaviour that results in the appearance of a vague, sometimes incomprehensible, even incoherent discourse and the use of strange terms.


Schizophrenia affects approximately 1% of the population, it is a chronic disease which displays very varied progression and development depending on the individual patient. Today, in almost half of all cases, medical and psychotherapeutic care allows for satisfactory remission and total or partial social reintegration. Compliance with treatment, the role of psychosocial interventions and support for the families of patients are essential issues because disorders generally begin in adolescence, can last a lifetime and therefore require long-term care. The disease is often diagnosed late. Its progression is characterised by phases of acute psychotic relapse in the early years, then a stabilisation with residual symptoms, of varying intensity according to the subjects. Depressive states often appear during an acute episode. They require specific treatment because of the high risk of suicide during this period. Over a lifetime, 40% of people with schizophrenia attempt suicide and 10% of all people with schizophrenia end their lives. The life expectancy of patients suffering from major somatic comorbidities (diabetes, cardiovascular diseases, etc.) is on average 10 years less than that of the general population, a major factor in desocialisation and precarity.

Treatments - the promise of research:

In research, the current model of the origin of schizophrenia is based on the interaction of several factors, both genetic and environmental. The progress of the work is essential to accurately identify the risk factors and thus promote better prevention.

To better understand the causes of the heterogeneity of the clinical forms of schizophrenia, to improve diagnostic and therapeutic tools, to predict the evolution of the disease and to discover new therapeutic pathways… the challenges of research are numerous. Many scientific disciplines are mobilised around one ambition: to promote tailor-made therapeutic strategies, personalised according to the profile of patients.

First, genetic vulnerability: many studies that have attempted to identify the genetic mutations in question conclude that different “profiles” exist, and this avenue remains to be explored.

Another major research challenge is the identification of environmental risk factors (inflammatory, infectious, toxic, migration, etc.) through prospective studies of large populations. The optimisation of this work consists of combining these two approaches: focussing more specifically on the interaction between genetic and environmental factors in the onset and progression of the disease. One environmental factor to which particular attention should be paid is early stress experienced in utero or in the perinatal period: the study of immune and inflammatory response dysfunctions which may contribute to the onset and development of the disease. Early disturbance of central nervous system maturation, linked to early stress, could be at the origin of the brain dysfunctions observed, in particular changes in connections between neurons. These connectivity abnormalities would have consequences during adolescence (a pivotal period of intense cognitive reorganisation and hormonal upheavals) and could favour the emergence of the disease.

Other promising pathways are autoantibodies (antibodies attacking the subject’s own system), present in 10 to 20% of patients suffering from schizophrenia, which disrupt the functioning of certain neuronal receptors. Finally, the link between chronic inflammation and premature ageing of the brain also represents an interesting avenue for explaining a lower intellectual level and more pronounced cognitive deficits in some patients.