Admixture analysis of age at symptom onset and age at disorder onset in a large sample of patients with obsessive-compulsive disorder.
BACKGROUND
A number of studies tested for the presence of different homogeneous subgroups of obsessive-compulsive disorder (OCD) patients depending on the age at onset (AAO). However, none of the various thresholds of AAO have been validated. No study examined whether age at symptoms onset (ASO) and age at disorder onset (ADO) each define specific and diverse OCD subgroups.


METHODS
We used normal distribution mixture analysis in a sample of 483 OCD patients to test whether we could identify subgroups of patients according to the AAO. We tested whether ASO and ADO had different distributions and identified different subgroups of OCD patients, and whether clinical correlates had similar patterns of associations with patients subgroups identified with ASO or ADO.


RESULTS
The mixture analysis showed a trimodal distribution for ASO (mean ASO: 6.9 years for the early onset, 14.99 years for the intermediate onset, and 27.7 years for the late onset component), and confirmed a bimodal distribution for ADO (mean ADO: 18.0 and 29.5 years). Significant differences in the clinical profile of the subgroups emerged, particularly when identified using ASO.


CONCLUSIONS
Limitations of our study are the retrospective investigation of AAO, and the fact that our sample may not represent the OCD population, as we enrolled patients referring to a tertiary center specialized in the treatment of OCD. Our findings need to be confirmed in community samples. Another limitation is the lack of information on medication status at enrollment.


CONCLUSIONS
Age at symptom onset and ADO showed distinct patterns of distributions. Similarly, phenotypic delineation was specific for ASO and ADO identified subgroups. Accurate clinical and biological profiling of ADO and ASO subgroups might show distinct genetic liabilities, ultimately leading to better nosological models and possibly to improved treatment decision making of OCD patients.
Rita Levi Montalcini Department of Neuroscience, Anxiety and Mood Disorders Unit, University of Turin, Italy Via Cherasco 11, 10126 Torino, Italy. Electronic address: umberto.albert@unito.it.
Umberto
U
Albert
Section of Psychiatry, Department of Public Health, Clinical and Molecular Medicine, University of Cagliari, Italy Via Liguria 13, 09127 Cagliari, Italy; Department of Pharmacology, Dalhousie University, Sir Charles Tupper Medical Building, 5850 College St, Halifax, Nova Scotia, Canada B3H 4R2.
Mirko
M
Manchia
Department of Psychiatry, University of Naples SUN, Napoli, Italy.
Alfonso
A
Tortorella
Department of Psychiatry, University of Naples SUN, Napoli, Italy.
Umberto
U
Volpe
Department of Mental Health, "San Luigi-Gonzaga" Hospital, University of Turin, Orbassano (TO), Italy, Regione Gonzole 10, 10043 Orbassano (To), Italy.
Gianluca
G
Rosso
Section of Psychiatry, Department of Public Health, Clinical and Molecular Medicine, University of Cagliari, Italy Via Liguria 13, 09127 Cagliari, Italy.
Bernardo
B
Carpiniello
Department of Mental Health, "San Luigi-Gonzaga" Hospital, University of Turin, Orbassano (TO), Italy, Regione Gonzole 10, 10043 Orbassano (To), Italy.
Giuseppe
G
Maina
D000293:Adolescent; D000328:Adult; D017668:Age of Onset; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009771:Obsessive-Compulsive Disorder / Q000175:diagnosis* / Q000453:epidemiology*; D012189:Retrospective Studies; D012720:Severity of Illness Index
Admixture analysis; Age at onset; Early onset; Obsessive–compulsive disorder