BACKGROUND: To assess whether bipolar disorder type I segregates into three clinically distinct sub-groups defined by age-at-onset. METHODS: Clinical data were available on 1369 individuals with DSM-IV bipolar I disorder. Mixture analysis was performed on the age-at-onset (AAO) data to determine whether they were composed of more than one normal distribution. Individuals were allocated to groups according to the results of the mixture analysis. Categorical logistic regression was then used to investigate relationships between AAO and nine clinical characteristics. RESULTS: The distribution of AAOs in our sample comprised a mixture of three normal distributions with means of 18.7 (SD=3.7), 28.3 (SD=5.5) and 43.3 (SD=9.1) years, with relative proportions of 0.47, 0.39 and 0.14 respectively. Individuals were allocated into three groups dependent on their AAO: < or = 22; 25-37; and > or = 40 years, producing a sample of 1225 individuals (144 with borderline values were excluded). Eight out of the nine clinical characteristics showed evidence for a statistical association with AAO group. LIMITATIONS: Systematic and non-systematic recruitment of participants. Some data relied on retrospective recall. CONCLUSIONS: Our results provide further robust evidence to suggest that the AAO distribution of individuals affected with bipolar disorder is composed of three normal distributions. Substantial clinical heterogeneity between the three AAO groups may reflect genetic heterogeneity within bipolar I disorder. Future genetic studies should consider AAO grouping as potential sub-phenotypes.
BACKGROUND: To assess whether bipolar disorder type I segregates into three clinically distinct sub-groups defined by age-at-onset. METHODS: Clinical data were available on 1369 individuals with DSM-IV bipolar I disorder. Mixture analysis was performed on the age-at-onset (AAO) data to determine whether they were composed of more than one normal distribution. Individuals were allocated to groups according to the results of the mixture analysis. Categorical logistic regression was then used to investigate relationships between AAO and nine clinical characteristics. RESULTS: The distribution of AAOs in our sample comprised a mixture of three normal distributions with means of 18.7 (SD=3.7), 28.3 (SD=5.5) and 43.3 (SD=9.1) years, with relative proportions of 0.47, 0.39 and 0.14 respectively. Individuals were allocated into three groups dependent on their AAO: < or = 22; 25-37; and > or = 40 years, producing a sample of 1225 individuals (144 with borderline values were excluded). Eight out of the nine clinical characteristics showed evidence for a statistical association with AAO group. LIMITATIONS: Systematic and non-systematic recruitment of participants. Some data relied on retrospective recall. CONCLUSIONS: Our results provide further robust evidence to suggest that the AAO distribution of individuals affected with bipolar disorder is composed of three normal distributions. Substantial clinical heterogeneity between the three AAO groups may reflect genetic heterogeneity within bipolar I disorder. Future genetic studies should consider AAO grouping as potential sub-phenotypes.
Authors: Michael Bauer; Tasha Glenn; Martin Alda; Ole A Andreassen; Raffaella Ardau; Frank Bellivier; Michael Berk; Thomas D Bjella; Letizia Bossini; Maria Del Zompo; Seetal Dodd; Andrea Fagiolini; Mark A Frye; Ana Gonzalez-Pinto; Chantal Henry; Flávio Kapczinski; Sebastian Kliwicki; Barbara König; Mauricio Kunz; Beny Lafer; Carlos Lopez-Jaramillo; Mirko Manchia; Wendy Marsh; Mónica Martinez-Cengotitabengoa; Ingrid Melle; Gunnar Morken; Rodrigo Munoz; Fabiano G Nery; Claire O'Donovan; Andrea Pfennig; Danilo Quiroz; Natalie Rasgon; Andreas Reif; Janusz Rybakowski; Kemal Sagduyu; Christian Simhandl; Carla Torrent; Eduard Vieta; Mark Zetin; Peter C Whybrow Journal: Bipolar Disord Date: 2012-05-21 Impact factor: 6.744
Authors: Ross J Baldessarini; Leonardo Tondo; Gustavo H Vazquez; Juan Undurraga; Lorenza Bolzani; Aysegul Yildiz; Hari-Mandir K Khalsa; Massimo Lai; Beatrice Lepri; Maria Lolich; Pier Mario Maffei; Paola Salvatore; Gianni L Faedda; Eduard Vieta; Mauricio Tohen Journal: World Psychiatry Date: 2012-02 Impact factor: 49.548
Authors: William Coryell; Jess Fiedorowicz; Andrew C Leon; Jean Endicott; Martin B Keller Journal: J Affect Disord Date: 2012-10-11 Impact factor: 4.839
Authors: Mirko Manchia; Mazda Adli; Nirmala Akula; Raffaella Ardau; Jean-Michel Aubry; Lena Backlund; Claudio Em Banzato; Bernhard T Baune; Frank Bellivier; Susanne Bengesser; Joanna M Biernacka; Clara Brichant-Petitjean; Elise Bui; Cynthia V Calkin; Andrew Tai Ann Cheng; Caterina Chillotti; Sven Cichon; Scott Clark; Piotr M Czerski; Clarissa Dantas; Maria Del Zompo; J Raymond Depaulo; Sevilla D Detera-Wadleigh; Bruno Etain; Peter Falkai; Louise Frisén; Mark A Frye; Jan Fullerton; Sébastien Gard; Julie Garnham; Fernando S Goes; Paul Grof; Oliver Gruber; Ryota Hashimoto; Joanna Hauser; Urs Heilbronner; Rebecca Hoban; Liping Hou; Stéphane Jamain; Jean-Pierre Kahn; Layla Kassem; Tadafumi Kato; John R Kelsoe; Sarah Kittel-Schneider; Sebastian Kliwicki; Po-Hsiu Kuo; Ichiro Kusumi; Gonzalo Laje; Catharina Lavebratt; Marion Leboyer; Susan G Leckband; Carlos A López Jaramillo; Mario Maj; Alain Malafosse; Lina Martinsson; Takuya Masui; Philip B Mitchell; Frank Mondimore; Palmiero Monteleone; Audrey Nallet; Maria Neuner; Tomás Novák; Claire O'Donovan; Urban Osby; Norio Ozaki; Roy H Perlis; Andrea Pfennig; James B Potash; Daniela Reich-Erkelenz; Andreas Reif; Eva Reininghaus; Sara Richardson; Guy A Rouleau; Janusz K Rybakowski; Martin Schalling; Peter R Schofield; Oliver K Schubert; Barbara Schweizer; Florian Seemüller; Maria Grigoroiu-Serbanescu; Giovanni Severino; Lisa R Seymour; Claire Slaney; Jordan W Smoller; Alessio Squassina; Thomas Stamm; Jo Steele; Pavla Stopkova; Sarah K Tighe; Alfonso Tortorella; Gustavo Turecki; Naomi R Wray; Adam Wright; Peter P Zandi; David Zilles; Michael Bauer; Marcella Rietschel; Francis J McMahon; Thomas G Schulze; Martin Alda Journal: PLoS One Date: 2013-06-19 Impact factor: 3.240