title: Improvement of cycloid psychosis following electroconvulsive therapy.
abstract: BACKGROUND
  The treatment of choice for cycloid psychosis has traditionally been electroconvulsive therapy (ECT), but there is a lack of studies on its effectiveness.
  
  
  OBJECTIVE
  The primary aim of this register study was to determine the rates of remission and response after ECT for cycloid psychosis. The secondary aim was to examine possible predictors of outcome.
  
  
  METHODS
  Data were obtained from the National Quality Register for ECT in Sweden. The study population was patients (n = 42) who received ECT for acute polymorphic psychotic disorder without symptoms of schizophrenia or for cycloid psychosis between 2011-2015 in 13 hospitals. Remission and response rates were calculated using Clinical Global Impression-Severity (CGI-S) and -Improvement scores, respectively. Variables with possible predictive value were tested using Chi-square and Fisher's exact test.
  
  
  RESULTS
  The response rate was 90.5%. The remission rate was 45.2%. Of 42 patients, 40 improved their CGI-S score after ECT (p < 0.001). The mean number of ECT treatments was 2.5 for non-responders and 7.0 for responders (p = 0.010). The mean number of ECT treatments did not differ significantly between remitters and non-remitters (7.2 vs 6.1, p = 0.31). None of the other investigated potential predictors was statistically significantly associated with outcome.
  
  
  CONCLUSIONS
  ECT is an effective treatment for cycloid psychosis. Future studies need to compare the outcome of ECT to that of other treatment strategies.
  
  
  CONCLUSIONS
  The high response rate with ECT indicates that cycloid psychosis is a clinically useful diagnosis.
authors.affiliation: a School of Medical Sciences , Örebro University , Örebro , Sweden.
authors.forename: Jonas
authors.initials: J
authors.lastname: Holm
authors.affiliation: b Clinical Epidemiology and Biostatistics, School of Medical Sciences , Örebro University , Örebro , Sweden.
authors.forename: Ole
authors.initials: O
authors.lastname: Brus
authors.affiliation: c Department of Clinical Neuroscience , Karolinska Institutet , Stockholm , Sweden.
authors.forename: Ullvi
authors.initials: U
authors.lastname: Båve
authors.affiliation: d Department of Medical Epidemiology and Biostatistics , Karolinska Institutet , Stockholm , Sweden.|e Institute of Neuroscience and Physiology , The Sahlgrenska Academy at Gothenburg University , Gothenburg , Sweden.
authors.forename: Mikael
authors.initials: M
authors.lastname: Landen
authors.affiliation: f Centre for Psychiatry Research, Department of Clinical Neuroscience , Karolinska Institutet , Stockholm , Sweden.
authors.forename: Johan
authors.initials: J
authors.lastname: Lundberg
authors.affiliation: g Center for Social and Affective Neuroscience, Department of Clinical and Experimental Medicine, Faculty of Health Sciences , Linköping University , Linköping , Sweden.|h Department of Psychiatry , Region Östergötland , Linköping , Sweden.
authors.forename: Pia
authors.initials: P
authors.lastname: Nordanskog
authors.affiliation: i Department of Neuroscience, Psychiatry , Uppsala University , Uppsala , Sweden.
authors.forename: Lars
authors.initials: L
authors.lastname: von Knorring
authors.affiliation: a School of Medical Sciences , Örebro University , Örebro , Sweden.
authors.forename: Axel
authors.identifier: http://orcid.org/0000-0001-7454-3065
authors.initials: A
authors.lastname: Nordenskjöld
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D004565:Electroconvulsive Therapy / Q000379:methods* / Q000639:trends; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D011618:Psychotic Disorders / Q000175:diagnosis / Q000453:epidemiology* / Q000628:therapy*; D012042:Registries; D012559:Schizophrenia / Q000175:diagnosis / Q000453:epidemiology / Q000628:therapy; D013548:Sweden / Q000453:epidemiology; D016896:Treatment Outcome; D055815:Young Adult
keywords: Cycloid psychosis; acute polymorphic disorder without symptoms of schizophrenia; electroconvulsive therapy; treatment outcome