SAN JUAN, P.R. – Just as with major depressive disorder, bipolar disorder, and schizophrenia, substance use disorders occur at a high rate in patients with psychotic major depressive disorder, according to a study presented at the annual meeting of the American Academy of Addiction Psychiatry.
For that reason, it is very important to assess those patients who have psychotic major depressive disorder (PMDD) for any co-occurring substance use disorders, John D. Matthews, M.D., said in a follow-up interview to his poster presentation.
Over the last 20 years, more evidence has emerged to suggest that major depressive disorder with psychotic features is a separate disorder and not just a more severe form of major depressive disorder, as it was previously considered.
It has a lot of symptoms in common with major depressive disorder, but with PMDD, there is also delusional thinking, hallucinations, or both, he said.
About one-quarter to one-third of the people who enter hospitals or programs because of major depressive disorder also have psychotic symptoms, he noted.
“It's actually as common as schizophrenia or bipolar disorder–about 1% of the general population,” said Dr. Matthews, who is director of inpatient research and training for the depression and clinical research program at Massachusetts General Hospital in Boston.
Dr. Matthews and his colleagues studied 52 inpatients and outpatients with PMDD to determine predictors for substance use disorders. They assessed severity of depression, number of depressive episodes, family history of depression, gender, age, and total number of Axis I diagnoses. The mean age of participants was 36 years, and 58% were women.
Family history of depression significantly predicted who would develop substance use disorder in this population, according to a logistic regression analysis.
“What we didn't predict was that the total number of Axis I diagnoses was a negative predictor,” Dr. Matthews said. “I don't have a good explanation for that.”
Together, these two predictors achieved an 84% correct classification for substance use disorder among people with PMDD.
Assessment of comorbidity was another aim of the study. “One thing missing in understanding the illness is what are the comorbid disorders, such as panic disorder or bipolar disorder. We know addictions frequently occur with those as well,” he said.
The researchers found that 17% of participants met criteria for a lifetime alcohol use disorder. In addition, 38% met criteria for a lifetime substance use disorder.
“We probably underestimated the number because they were involved in pharmacologic trials, and we had excluded those with a 6-month or less history of substance use disorder,” Dr. Matthews explained.
The substance use assessment was a secondary, ad hoc analysis of a pharmacologic intervention trial.
A prospective study is planned to assess substance use disorders in patients with PMDD without restricting the exclusion criteria.