Given the untoward effects associated with CUD, there is value in identifying risk factors that will facilitate early intervention.
A cross-sectional, community-based study was conducted to identify familial aggregation and coaggregation of CUD and mood disorders. Data were collected by semi-structured diagnostic interviews and family history reports.
The primary outcome was lifetime risk of CUD among first-degree relatives.
Of the 586 probands, 186 and 55 were diagnosed with bipolar disorder and CUD, respectively. Of the 698 1st-degree relatives, 91 and 68 were diagnosed with bipolar disorder and CUD, respectively.
A diagnosis of CUD in probands was associated with a diagnosis of CUD in 1st-degree relatives (aOR=2.64). A diagnosis of bipolar disorder II in probands was associated with a diagnosis of CUD in 1st-degree relatives (aOR=2.57).
In contrast, a diagnosis of bipolar disorder I and major depressive disorder in probands was not associated with a diagnosis of CUD in 1st-degree relatives. Among 1st-degree relatives, however, a diagnosis of bipolar disorder II and major depressive disorder was associated with a diagnosis of CUD (aOR = 4.50 and 3.64, respectively). First-degree relatives with familial and individual histories of bipolar disorder II had the strongest association with a diagnosis of CUD.
The onset of mood disorders was shown to often precede the diagnosis of CUD in probands and 1st-degree relatives.