Secular trends in first hospitalizations for major mood disorders with comorbid substance use

Abstract

In the past half-century, the incidence of major mood disorders reportedly has risen, and onset age, diminished. Substance-use disorders (SUDs) are commonly comorbid with mood disorders and may influence their course and outcome. Since secular relationships of these disorders remain unknown, we evaluated medical records of 421 patients (233 men, 188 women) at first-lifetime admissions for major depression, mania or mixed bipolar episodes at a public hospital in Italy during 1978-2002, updated diagnoses to DSM-IV criteria, and compared selected factors between subjects with vs. without SUDs, seeking evidence of secular trends in SUDs in association with early mood disorders. SUD was diagnosed in 122 patients (29.0%). SUD risk was greatest in young males. Relative risk (RR) of diagnostic association with SUDs ranked: mixed states (RR 1.80), mania (RR 1.06), depression (RR 0.55). Annual rates of comorbid SUD and mood disorders increased continuously over the 25-yr epoch for all substances (r = 0.640, p < 0.001). Age at onset of illness and at first hospitalization (averaging 36 yr and 38 yr) were unrelated to year of hospitalization in this relatively brief sampling, but patients with SUD were younger at onset and admission, overall. Clinical Global Impression (CGI) ratings of illness severity at hospitalization and discharge were stable across years. These findings indicate a secular increase of comorbid SUD among first admissions for mood disorder, especially in young males, with a parallel increase in the proportion of bipolar disorder diagnoses over the past quarter of a century.