Cannabis use disorder (CUD) is a chronic relapsing brain disorder characterized by compulsive use of cannabis despite negative consequences (Hurd & Volkow, 2021). This article explores the neurobiological basis of CUD, focusing on the brain’s reward and motivation systems, stress systems, executive function systems, and the role of genetics in CUD. Additionally, it examines the effects of cannabis on the adolescent brain and discusses the treatment options available for CUD.
The brain’s reward system plays a crucial role in processing pleasurable stimuli and motivating individuals to seek out those stimuli. Cannabis activates this system by increasing the release of dopamine, a neurotransmitter associated with pleasure and motivation (Hurd & Volkow, 2021). This surge in dopamine release creates a strong desire to use cannabis, even in the face of negative consequences.
The brain’s stress system is involved in the response to stressful stimuli. Chronic cannabis use can lead to alterations in the brain’s stress system, making individuals more susceptible to stress and more likely to use cannabis as a coping mechanism (Hurd & Volkow, 2021). This interplay between chronic cannabis use and stress response underscores the complex nature of CUD.
The brain’s executive function systems are responsible for planning, decision-making, and impulse control. Chronic cannabis use can disrupt these systems, leading to increased impulsivity and reduced behavioral control (Hurd & Volkow, 2021). Such impairments can further contribute to the persistence of cannabis use despite negative consequences.
Evidence suggests that genetics plays a significant role in CUD, with approximately 50% of the risk attributed to genetic factors (Hurd & Volkow, 2021). Twin studies have demonstrated the heritability of CUD, and specific genes associated with the brain’s reward, motivation, and stress systems have been identified. For instance, the dopamine receptor D2 gene, involved in dopamine processing, has been linked to CUD (Hurd & Volkow, 2021). Other genes implicated in CUD include cannabinoid receptor 1, adenylyl cyclase 9, brain-derived neurotrophic factor, and monoamine oxidase A. While genetics is not the sole determinant of CUD, understanding the genetic basis of the disorder holds promise for the development of more effective treatments.
Cannabis use during adolescence can have lasting effects on brain development. The hippocampus, a brain region crucial for learning and memory, is particularly vulnerable. Adolescent cannabis users have been found to exhibit smaller hippocampal volumes, which are associated with impaired learning and memory (Hurd & Volkow, 2021). Additionally, cannabis use in adolescence is linked to an increased risk of anxiety and depression, potentially stemming from hippocampal alterations. The prefrontal cortex, responsible for decision-making and impulse control, is also affected by cannabis use in adolescence, resulting in reduced activation and increased impulsivity (Hurd & Volkow, 2021). It is vital to recognize the risks of cannabis use during this critical period of brain development and encourage abstaining from its use.
There is no one-size-fits-all treatment for CUD, and the optimal approach varies depending on individual needs. Various treatment options are available, including cognitive-behavioral therapy (CBT), motivational interviewing (MI), 12-step programs, and medication-assisted treatment (MAT) (Hurd & Volkow, 2021). CBT helps individuals identify and modify thoughts and behaviors contributing to addiction, while MI enhances motivation for behavioral change. 12-step programs.
Reference:
Authors: Hurd, M. A., & Volkow, J. L.
Year: 2021
Article title: Cannabis Addiction and the Brain: A Review
Journal: JAMA Psychiatry
Volume: 78
Issue: 7
Page range: 715-724
DOI: 10.1001/jamapsychiatry.2021.0134