La catatonie est un concept dont la place au sein de la nosologie psychiatrique a toujours été mouvante et incertaine depuis sa création en 1874 par Kahlbaum. Longtemps associée à la schizophrénie et de moins en moins diagnostiquée, elle connaît depuis 10 ans un nouvel essor, avec d'une part la définition de critères diagnostiques précis, et d'autre part la mise en évidence d'une association préférentielle avec les troubles de l'humeur. Trois signes au moins sont nécessaires pour porter avec certitude le diagnostic, parmi : immobilité/stupeur, mutisme, négativisme, oppositionisme, maintien des postures, catalepsie, obéissance automatique/compliance excessive, phénomènes d'écho, rigidité, verbigération, retrait/refus des aliments. Ce diagnostic est fondamental, car il conduit à l'utilisation de thérapeutiques spécifiques, les ECT et le lorazépam, indispensables si l'on veut éviter la survenue de la forme létale. L'effet de cette benzodiazépine n'a été découvert et étudié que récemment. Plus largement, les différents travaux sur la catatonie reposent les questions de la position nosologique et de l'étiopathogénie ambiguës du trouble.

Catatonia was first described in 1874 by Kahlbaum as being a cyclic disease mixing motor features and mood variations. Because most cases ended in dementia, Kraepelin recognized catatonia as a form of dementia praecox and Bleuler included it within his wide group of schizophrenias. This view influenced the psychiatric practice for more than 70 years. But catatonia was recently reconsidered and this because of the definition of more precise diagnosis criteria, the discovery of a striking association with mood disorders, and the emphasis on effective therapeutics. Peralta et al empirically developed a performant diagnostic instrument with the 11 most discriminant signs among catatonic features. Diagnostic threshold is three or more signs with sensitivity of 100 % and specificity of 99 %. These signs are : immobility/stupor (extreme passivity, marked hypokinesia) ; mutism (includes inaudible whisper) ; negativism (resistance to instructions, contrary comportment to whose asked) ; oppositionism, other called gegenhalten (resistance to passive movement which increases with the force exerted) ; posturing (patient adopts spontaneously odd postures) ; catalepsy (patient retains limb positions passively imposed during examination ; waxy flexibility) ; automatic obedience (exaggerated co-operation to instructed movements) ; echo phenomena (movements, mimic and speech of the examiner are copied with modification and amplifications) ; rigidity (increased muscular tone) ; verbigeration (continuous and directionless repetition of single words or phrases) ; withdrawal/refusal to eat or drink (turning away from examiner, no eye contact, refusal to take food or drink when offered). Using this diagnostic tool, prevalence of catatonic syndrome appears to be close to 8 % of psychiatric admissions. Other signs are also common but less specific : staring, ambitendance, iterations, stereotypes, mannerism, overactivity/excitement, impulsivity, combativeness. Some authors complete this description by adding an affective dimension which is considered specific. Clinical forms are differentiated according to evolution : acute, chronic and periodic forms exist ; and symptomatology : excited catatonias have a best prognostic than retarded catatonias. Malignant catatonia is the most studied form because of its severity and high rate of mortality (25 %) ; catatonic patients develop autonomic disturbances with labile blood pressure, hyperthermia, diaphoresis, etc. Malignant catatonia requires ECT intervention in emergency. While catatonias due to general medical conditions are well admitted (first concerned are neurologic etiologies) and concern 14,1 % of catatonias, psychiatric comorbidity remains a problem. The documented decline in the proportion of patients with schizophrenia diagnosed as catatonic is congruent with the fact that most studies highlight the strong association between catatonia and mood disorders. However, customary clinical practice continues to overvalue diagnostic of schizophrenia because catatonic symptoms are recognized as schizophrenic and schizophrenia corresponds to a pharmacological target. Other authors stress that on average 20 to 40 % of catatonias are idiopathic. Conceptual proximity between catatonic symptomatology and extrapyramidal syndrome could give some ways for neurobiological grasp of the trouble ; mesolimbic and mesostriatal dopaminergic imbalance in a frontal lobe-basal ganglia-brainstem system is supposed to be involved. Treatment procedure could be standardized as follows : 1) Withhold neuroleptic medication. Those drugs are proven to be lethal when catatonic symptoms are developed ; 2) Investigations to exclude treatable physical disorders (including standard blood laboratory tests, urinary drug screening, electroencephalogram and brain computerized tomography) ; 3) Trial of lorazepam. This therapeutic is safe and 80 % effective. We propose to administer an initial oral 2,5 mg challenge ; catatonic signs are rated after the first hours. If necessary, the patient could receive 3 mg/day with a 6-day full dose treatment and then, treatment would progressively be reduced ; 4) If the patient failed to respond to lorazepam, ECT are needed ; 5) Earlier use of ECT is recommended if autonomic instability or hyperthermia appears and malignant catatonia is suspected. In conclusion, catatonia has always had an unstable and blurred place in the psychiatric nosography since its first description. It has been incorporated within the group of schizophrenias and underdiagnosed for a long time, but has been predominantly associated with mood disorders for the last ten years. Psychopathological considerations, particularly on cognitive and affective status of catatonic patients, should clarify the nosologic discussion.