The link between mood disorders and cannabis use disorder in families

By Jules Murtha | Medically reviewed by Amanda Zeglis, DO, MBA
Published July 5, 2022

Key Takeaways

  • Patients with mood disorders like major depressive disorder (MDD) and bipolar disorder (BD) tend to use cannabis at higher rates than those without a mood disorder.

  • Unlike MDD and BD-I, BD-II may be linked to a higher risk of cannabis use disorder (CUD) among family members.

  • For patients with psychiatric disorders and CUD, treating their mental illness may result in a reduction of cannabis use.

While cannabis remains illegal on a federal level, over half of the US now allows it for both medical and recreational use. If there are clear advantages to the legalization of cannabis, one would be its public health and safety benefits, according to an article published Review of Policy Research.[]

The intersection of cannabis use disorder (CUD) and mood disorders in patients, however, may pose challenges to individuals who have a family history of mood disorders.

As research on the link between CUD and mood disorders become more widely available, doctors can address mental illnesses and reduce the use of cannabis with several types of therapy.

MDD and CUD prevalence in families

Major depressive disorder (MDD) is characterized by anhedonia, persistent negative affect, and disturbed sleep and appetite.[]

Research has shown that patients who have MDD are more likely to use cannabis at higher rates than those who do not have MDD.

A study published by JAMA Psychiatry looked at whether CUD is familial and associated with MDD, BD-I, and BD-II.[]

The study was composed of 586 probands and 698 first-degree relatives. Of the probands, 67.4% were female, as were 62.6% of the relatives. The mean age for probands was 47.5 years; 49.6 years was the average for relatives.

The findings showed that on its own, the presence of CUD among probands generally led to an increase of CUD in relatives. The presence of MDD, however—which appeared in 32.8% of probands—didn’t show a greater association with CUD in relatives.

While other evidence points to a four-fold risk of depression developing among cannabis users, the JAMA study’s results could rule out a greater risk of passing CUD to relatives who have a family history of MDD.

BD and CUD occurrence in families

Similar to patients with MDD, patients who have bipolar disorder (BD), which entails cyclical changes in mood ranging from depressive states to manic states, also have a tendency to use cannabis more often than individuals without the disorder.[]

According to the JAMA study, BD-I, which 19.5% of probands had, was not associated with a higher risk of CUD in relatives.

BD-II, on the other hand, was. Of the probands, 12.3% had BD-II. The relatives of these participants showed a significantly increased rate of CUD. The study authors stated the clinical importance of this result.

"The increase in risk of CUD among relatives of probands with BP-II suggests that CUD may share a common underlying diathesis with BP-II."

Quick, et al.

“Taken together with the temporal precedence of depression and mania with respect to CUD onset, these findings highlight a potential role for BP-II intervention as CUD prevention,” they added.

CUD treatment options

Research is lacking on what the most effective treatment option is for people with BD-II and CUD. However, studies have shown that treating the mental illnesses of patients with psychiatric disorders and CUD may result in a reduction of their cannabis use.

For now, doctors can look at available treatment options for CUD, which don’t yet include medications.

The National Institute on Drug Abuse published an article detailing three types of therapy for CUD:[]

Cognitive-behavioral therapy. This is a type of psychotherapy that helps patients recognize and address problematic behaviors. In doing so, they can garner more self-control with respect to mood and substance concerns.

Motivational enhancement therapy. This therapy entails a systematic type of intervention with the goal of rapidly increasing the patient’s motivation to change and engage in treatment. While it’s not a treatment in and of itself, it does act as a catalyst for available treatment options.

Contingency management. This includes a close look at the patient’s behaviors. When the patient exhibits a target behavior, they are given a tangible, positive, reward. That reward is taken away if the patient fails to exhibit the desired behavior.

What this means for you

Patients who have mood disorders, such as MDD or BD, are more likely to use cannabis than patients who do not. Emerging evidence points to the possibility that BD-II could be related to a greater likelihood of CUD in family members. Further research is necessary to confirm effective treatment options for this specific comorbidity, but doctors can treat patients’ underlying mood disorders and further reduce their cannabis use with certain approved therapies.

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