Substance Abuse and Depression -- Which Comes First?

Although knowledge gaps still exist, researchers are moving closer to a better understanding of the link between substance abuse and internalizing disorders.

When it comes to the study of substance abuse and internalizing disorders in adolescents, there are still significant gaps in knowledge, according to a presentation delivered on Wednesday, Oct. 27, at the AACAP 57th Annual Meeting in New York, NY.

According to Naomi R. Marmorstein, PhD, Rutgers University, Camden, NJ, research on adolescents has focused primarily on externalizing disorders, with the model of substance abuse disorder (SUD) as “self-medication,” which often is not the case. In her presentation, Marmorstein examined the associations between internalizing disorders (IDs) and SUDs in adolescents, using data from a community sample.

In her research, she has studied models that take into account factors including genetics, other comorbid disorders, early drug use, and gender. Some of the key findings are as follows:

  • Although genetics don’t fully account for the association between ID and SUD, they are likely to play a contributing role
  • Other environmental factors associated with risk for SUDs among adolescents include stress, abuse, family conflict/low monitoring, poverty and parental psychopathology
  • Social anxiety was found to predict alcohol consumption in young adults (however, it is unclear whether this applies to adolescents or those with clinical disorders)
  • Age at first use of substances tends to be earlier in youths with depressive symptoms and anxiety symptoms
  • Generalized anxiety is linked to quicker progression from first use of substances to dependence on substances or abuse
  • IDs seem to be more related to alcohol problems than consumption levels (depressed kids not at risk for heaviest drinking, but for more problems related to drinking)
  • It is more likely that SUDs predict onset of depression than the reverse
  • Although evidence is insufficient, there is a belief that closers associations between IDs and SUDs exist in females
  • Heavy users of cannabis may be at increased risk for developing major depressive disorder

It is critical, Marmorstein added, for providers to carefully asses the onset and patterns of symptoms in each individual patient, and to avoid the assumption that SUDs are due to self-medication.

In another presentation, Christian Thurstone, MD, University of Colorado Denver, discussed pharmacological treatments of co-occuring internalizing disorders and substance abuse disorders, a topic that has gained momentum in the child and adolescent psychiatry community.

Thurstone highlighted a study published by colleagues at University of Colorado that evaluated the effect of fluoxetine hydrochloride vs placebo on SUD, major depressive disorder (MDD), and conduct disorder (CD) in adolescents also receiving cognitive behavioral therapy (CBT). The CBT sessions included functional analysis of drug abuse, and interview sessions that focused on setting goals, coping with cravings, problem solving, and anger management.

Results from the study showed that fluoxetine plus CBT experienced demonstrated greater efficacy than placebo and CBT on one but not both depression measures and was not associated with greater decline in self-reported substance use or CD symptoms. Researchers noted that use of cognitive behavioral therapy may have contributed to higher-than-expected treatment response.

Other medications—including sertraline and bupropion—are being researched as possible treatments for depression, and may offer more options in the future, said Thurstone, who provided brief summaries of the recommendations provided by the AACAP and the American Psychiatric Association (APA):

AACAP Guidelines (2002)

  • Co-morbid conditions should be appropriately treated
  • Emerging research states that pharmacological treatments can be used safely and effectively in adolescents with SUDs
  • Use caution with scheduled medications

APA Guidelines

  • If treatment of co-occuring psychiatric conditions doesn’t occur, it’s less likely that SUD treatment will be successful
  • In most patients, the medications targeted for treating a specific disorder are recommended whether or not there is co-occurring SUD
  • Be cautious of factors such as medication non-adherence, synergy of medications, intentional or unintentional overdose, and drug/drug interactions

Finally, Thurstone reminded all clinicians that “a tremendous opportunity exists” for research in this area, and encourages all who are interested to participate in studies.