Patients with co-occurring depression and substance use disorders are less likely to receive adequate depression treatment, researchers found in a retrospective cohort study published in the American Journal of Psychiatry In Advance involving 53,034 patients who were diagnosed in the United States Veterans Health Administration (VHA) in fiscal year 2017.

Past research has indicated that effectively treating co-occurring depression and substance use disorders involves treating both disorders simultaneously (depression with pharmacotherapy, psychotherapy or both) and that only about half of patients with both diagnoses receive treatment for depression, the researchers said. Thus, investigators wanted to ascertain whether individuals with both disorders receive a similar level of care in outpatient depression treatment as those individuals who have depression but not substance use disorders.

The researchers included 53,034 patients of the VHA who experienced a new episode of depression in fiscal year 2017, 30 days before or after receiving a depression diagnosis that indicated active depression (Patient Health Questionnaire (PHQ-2 greater than 2 or PHQ-9 greater than 9) and excluded patients who had already received a depression diagnosis or treatment (psychotherapy or prescription) for depression in the year before the index diagnosis date.  The researchers also excluded patients who had bipolar disorder, personality disorders or developmental disorders. The cohort included 7516 patients who had received a substance use disorder diagnosis in the year before receiving the depressive disorder diagnosis.

To determine conformance with the adequate acute-phase treatment and the adequate continuation-phase treatment measures of the Healthcare Effectiveness Data and Information Set (HEDIS), the researchers investigated whether the patients received a prescription within the 90 days following the depression diagnosis for an antidepressant for at least 84 of the 114 days following the initial prescription and continuing antidepressant medication for 180 of the first 231 days following the initial prescription. They also investigated whether the patients received a psychotherapy session for depression within 90 days of the index depression diagnosis and at least 3 psychotherapy sessions in the 12 weeks following the first therapy session.


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They created 4 logistic regression models to determine whether there was an association between substance use disorder diagnosis, adequate acute- and continuation-phase antidepressant or psychotherapy, adjusted for covariates and evaluated with each individual substance use disorder.

The researchers found that 28,081 of the 53,034 patients in the cohort received any antidepressant treatment and 18,484 patients received any psychotherapy for depression within 90 days following their diagnosis. The 7,516 patients with substance use disorders had lower odds of receiving acute or continuation phases of antidepressants (acute phase, adjusted odds ratio (AOR)=0.79, 95% CI=0.73, 0.84, P <.001; continuation phase, AOR=0.74, 95% CI=0.69, 0.79, P <.001) or psychotherapy (acute phase, AOR=0.87, 95% CI=0.82, 0.91, P <.001; continuation phase, AOR=0.81, 95% CI=0.73, 0.89, P <.001) that met the guidelines.

Without adjusting for covariates, the researchers found that 59.4% of the 7,516 patients who had both a depressive disorder diagnosis and a substance use disorder diagnosis received acute-phase antidepressant treatment while 66.2% of the patients without substance use disorders received that treatment. The difference in rate of treatment for continuation-phase antidepressant treatment was greater: 36.3% of patients with co-occurring substance use disorders received treatment while the rate rose to 44.8% for patients without both disorders.

Psychotherapy was more frequently provided in both acute and continuation forms to those without substance use disorders (35.4%, 32.2% respectively) than to those with both disorders (31.6%, 26.8%).

Of the patients with substance use disorders who received treatment, 1,117 received psychotherapy and 2,390 received antidepressant treatment in mental health clinics, 1,014 received psychotherapy and 1,287 received antidepressants in primary care/primary care mental health integration clinics, 83 received psychotherapy and 102 received antidepressants in substance use disorder specialty clinics, and 163 received psychotherapy and 265 received antidepressants in other clinics.

“By assessing both antidepressant medications and psychotherapy for depression, we found that psychotherapy does not account for the lower utilization of medication-based interventions among patients with comorbid substance use. Indeed, receipt of guideline-concordant antidepressant and psychotherapy treatments is consistently lower across depression care metrics among those with comorbid substance use disorders,” the researchers said.

Limitations of the study included the sole inclusion of veterans in care within the VHA system, the exclusion of services received outside the VHA system and the emphasis on solely the indicators of adequate acute and continuation phases of care to the exclusion of other facets of high-quality care.

“Although the magnitude of difference (approximately 20% lower odds) may seem modest, both depression and substance use disorders are highly prevalent, such that even modest differences amount to large numbers of individuals. These findings highlight the opportunity for increased depression treatment across both treatment modalities for those with substance use disorders to achieve guideline-concordant care.”

Reference

Coughlin LN, Pfeiffer P, Ganoczy D, Lin LA. Quality of outpatient depression treatment in patients with comorbid substance use disorder (published online October 29, 2020). AJP in Advance. doi: 10.1176/appi.ajp.2020.20040454