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People with Substance Use Disorder Can Have Persistent Deficits in Executive Functioning Despite Treatment

Key findings

  • Patients with substance use disorder continued to manifest clinically significant deficits in executive functioning after completing a four-week intensive outpatient treatment program
  • These deficits persisted despite abstinence or low levels of substance use and despite improvement in depression
  • Substance use disorder treatment programs should consider assessing executive functioning at intake, so that treatment can be individualized as needed

Impairments in executive functioning are thought to affect 30-80% of people with substance use disorder (SUD). Documented examples include problems with sustained attention, working memory, visuospatial ability and decision-making.

In a previous studyJames W. McKowen, PhD, clinical director for the Addiction Recovery Management Program, and Timothy E. Wilens, MD, co-director of the Center for Addiction Medicine, determined that patients with SUD who dropped out of an intensive outpatient program had more severe impairment in executive functioning than those who completed the program.

In a follow-up study, reported in The American Journal on Addictions, the same research team found that executive functioning did not appear to improve in patients who completed the month-long program. These persistent deficits may affect patients' ability to participate in treatment, the team notes.

In the original study, participants had to be diagnosed with substance use or dependence (excluding nicotine and caffeine) and be 18 to 65 years old. Exclusion criteria included a history of psychosis within the past two months, history of schizophrenic spectrum disorder or significant risk of harming self or others. The program was four weeks long and involved two hours of group therapy three days per week.

Thirty patients enrolled in the program, and 20 completed it. However, five patients were lost to follow-up. Therefore, the sample for the follow-up study was 15 patients who completed the following self-report questionnaires before and after the treatment program:

  • Timeline Followback, in which the patient reports past 30-day substance use in a calendar format
  • Behavior Rating Inventory of Executive Functioning–Adult (BRIEF-A)
  • Adult ADHD (Attention Deficit/Hyperactivity Disorder) Self-Report Scale
  • Beck Depression Inventory, second edition
  • Beck Anxiety Inventory
  • Leeds Dependence Questionnaire, which assesses symptoms and behaviors associated with alcohol and drug dependence

The patients also had to have pre- and post-program scores on the Cambridge Neuropsychological Test Automated Battery (CANTAB), a computerized test system that evaluates a range of executive functions. The six subtests assessed include:

  • Spatial working memory
  • Spatial planning
  • Visual discrimination and flexibility of attention
  • Vigilance
  • Reaction time
  • Ability to take risks and make decisions without impulsivity

The researchers found that substance use remained stable and minimal during the program. There was a significant improvement in symptoms of depression, though not anxiety or ADHD.

Even so, patients continued to manifest clinically significant impairment in executive functioning. At follow-up, all BRIEF-A scores were just below the clinical threshold for impairment, and there was a significant improvement only on the organization subscale.

There was no significant change on any CANTAB test between baseline and follow-up. Furthermore, all CANTAB scores were below what the test makers consider to be average for healthy people.

Patients with inconsistent attendance or tardiness at treatment group meetings are frequently conceptualized as being "not ready" or "not motivated," the researchers note. The truth, they say, may be that such patients are struggling with impairments in executive function that make it difficult to adhere to standard treatments.

For example, treatment for SUD typically requires knowing and remembering when and where to attend group meetings, recalling medication instructions, being able to follow cognitive behavioral therapy and applying skills taught in therapy sessions to stressful life situations.

The research team recommends assessing the executive functioning of new patients with SUD and adapting interventions and clinic workflow to provide more individualized treatment.

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