Birth-cohort and dual diagnosis effects on age-at-onset in Brazilian patients with bipolar I disorder

Authors

  • P. V. Da Silva Magalhães,

    1. Bipolar Disorders Program & INCT Translational Medicine, Hospital de Clínicas de Porto Alegre, Universidade Federal do Rio Grande do Sul, Porto Alegre, Brazil
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  • F. A. Gomes,

    1. Bipolar Disorders Program & INCT Translational Medicine, Hospital de Clínicas de Porto Alegre, Universidade Federal do Rio Grande do Sul, Porto Alegre, Brazil
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  • M. Kunz,

    1. Department of Psychiatry, University of British Columbia, Vancouver, BC, Canada
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  • F. Kapczinski

    1. Bipolar Disorders Program & INCT Translational Medicine, Hospital de Clínicas de Porto Alegre, Universidade Federal do Rio Grande do Sul, Porto Alegre, Brazil
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Professor Flávio Kapczinski MD, PhD, Director – Bipolar Disorders Program, Hospital de Clínicas, UFRGS, Porto Alegre, RS, Brazil.
E-mail: kapcz@terra.com.br

Abstract

Objective:  Substance use disorders and birth-cohort have been associated with an earlier onset in bipolar disorder (BD). This study aimed at evaluating the inter-relations of these factors in age-at-onset in bipolar illness.

Method:  Two-hundred and thirty patients with bipolar I disorder were cross-sectionally evaluated. Patients were categorized into four age groups for analysis. Lifetime comorbidity and age-at-onset were derived from the Structured Clinical Interview for DSM-IV.

Results:  There was a strong linear association between age group and age-at-onset. Lifetime alcohol and drug use disorders were also associated with age-at-onset. Illicit drug and alcohol use disorders and age group remained significant in the multivariate model. No interactions appeared.

Conclusion:  Both age group and dual diagnoses had strong and independent impacts on age-at-onset in out-patients with BD. Substance abuse may be partly accountable for earlier symptom onset, but other features of BD in younger generations are still in need to be accounted for.

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