Many people suffer from more than one mental disorder at a given time.
In particular, depressive illnesses tend to co-occur with substance abuse and anxiety disorders. Wo men are nearly twice as likely to suffer from major depression than men. However, men and women are equally likely to develop bipolar disorder. While major depression can develop at any age, the average age at onset is the mid-20s. More than 90 percent of people who commit suicide have a diagnosable mental disorder - most commonly a depressive disorder or a substance abuse disorder.