Key Highlights
  • Marijuana (cannabis) is a psychoactive plant containing over 100 cannabinoid compounds
  • THC (delta-9-tetrahydrocannabinol) is the primary psychoactive component
  • Most commonly used federally illicit drug in the United States
  • Acts on the endocannabinoid system, affecting mood, memory, appetite, and pain perception
  • Approximately 16.3 million Americans had cannabis use disorder in 2021
  • Today's marijuana is significantly more potent than decades past (average THC ~15-25% vs. ~4% in 1990s)
  • Cannabis use disorder is recognized in the DSM-5-TR with defined diagnostic criteria
  • Adolescent use carries particular risk for cognitive development and mental health

Published: February 2026 | Last Updated: February 2026 | Reading Time: 6 min

What Is Marijuana?

Marijuana, also known as cannabis, weed, pot, or numerous other colloquial names, is a psychoactive plant of the genus Cannabis (primarily Cannabis sativa, Cannabis indica, and hybrids thereof). The plant contains over 100 chemical compounds called cannabinoids, along with terpenes and flavonoids that contribute to its effects and aroma. Delta-9-tetrahydrocannabinol (THC) is the cannabinoid primarily responsible for marijuana's intoxicating effects, while cannabidiol (CBD) is a non-intoxicating compound that has garnered attention for potential therapeutic applications.

Forms of Marijuana

Cannabis is consumed in multiple forms: dried flower (buds) that is smoked or vaporized, concentrates and extracts (wax, shatter, oils) with THC concentrations of 60-90%, edibles (food products infused with cannabis), tinctures (liquid extracts applied under the tongue), and topical preparations applied to the skin. The method of consumption significantly affects onset time, duration of effects, and intensity of the experience.

Legal Status

Marijuana occupies a unique legal position. It remains classified as a Schedule I controlled substance under federal law. However, as of 2026, the majority of U.S. states have legalized marijuana for medical use, and a growing number have also legalized recreational adult use. New Jersey legalized recreational cannabis in 2021. This federal-state conflict creates complex regulatory and legal implications.

How Marijuana Affects the Brain

The Endocannabinoid System

Marijuana's effects are mediated through the endocannabinoid system (ECS), a widespread neurotransmitter system that the body uses to regulate mood, appetite, pain, memory, immune function, and numerous other physiological processes. The ECS consists of endogenous cannabinoids (anandamide and 2-AG), cannabinoid receptors (CB1 and CB2), and enzymes that synthesize and degrade endocannabinoids.

THC's Mechanism of Action

THC mimics the endocannabinoid anandamide by binding to CB1 receptors, which are concentrated in brain regions governing pleasure, memory, concentration, sensory perception, movement, and time perception. By activating these receptors, THC alters normal neurotransmitter signaling, producing the characteristic "high" as well as the drug's therapeutic and adverse effects.

Short-Term Effects

Acute effects of marijuana include euphoria, relaxation, altered perception of time, heightened sensory experiences, increased appetite, impaired short-term memory, reduced coordination, and anxiety or paranoia (particularly at high doses or in inexperienced users). Effects begin within minutes when smoked or vaped and within 30-90 minutes when ingested orally.

Marijuana and Dependency

Cannabis Use Disorder

Contrary to the persistent myth that marijuana is not addictive, the DSM-5-TR recognizes cannabis use disorder as a clinical diagnosis. Approximately 9% of people who use marijuana will develop dependence, rising to approximately 17% among those who begin in adolescence and 25-50% among daily users.

Rising Potency Concerns

Modern marijuana is substantially more potent than the cannabis available decades ago. Average THC concentrations have increased from approximately 4% in the early 1990s to 15-25% in today's flower products, with concentrates reaching 60-90%. Higher potency is associated with increased risk of dependency, psychotic symptoms, and cannabis hyperemesis syndrome.

Withdrawal Symptoms

Cannabis withdrawal is recognized in the DSM-5-TR and typically begins 1-2 days after cessation in dependent users, peaking around day 4-7. Symptoms include irritability, anger, anxiety, sleep difficulties, decreased appetite, restlessness, depression, and physical symptoms such as headaches, sweating, and abdominal pain.

Health Considerations

Cognitive Effects

Research consistently demonstrates that heavy marijuana use during adolescence — when the brain is still developing — can cause lasting impairments in attention, memory, processing speed, and executive function. The effects appear most pronounced in those who begin regular use before age 16.

Mental Health

Growing evidence links regular cannabis use to increased risk of psychotic disorders, particularly in genetically predisposed individuals. Heavy use is also associated with higher rates of anxiety, depression, and suicidal ideation, though the causal relationships are complex and bidirectional.

Respiratory Effects

Smoking marijuana exposes the lungs to many of the same irritants and carcinogens found in tobacco smoke. Regular smoking is associated with chronic bronchitis symptoms, airway inflammation, and impaired lung function, though the link to lung cancer remains less clear than with tobacco.

Treatment for Cannabis Use Disorder

Treatment for marijuana dependency primarily involves behavioral therapies including cognitive-behavioral therapy, motivational enhancement therapy, and contingency management. No FDA-approved medications currently exist specifically for cannabis use disorder, though several candidates are under investigation. Support groups and structured outpatient programs provide ongoing recovery support.

Frequently Asked Questions

Can you get addicted to marijuana?

Yes. Approximately 9% of marijuana users develop cannabis use disorder. The risk is higher among those who start young, use daily, and use high-potency products. Withdrawal symptoms upon cessation confirm the development of physical dependence.

Is marijuana a gateway drug?

The "gateway drug" theory is oversimplified. While most people who use harder drugs did use marijuana first, the vast majority of marijuana users do not progress to other illicit substances. Correlation does not equal causation — shared risk factors including genetics and environment likely explain the association.

How long does marijuana stay in your system?

THC metabolites are fat-soluble and can be detected in urine for 3-10 days after occasional use, 2-4 weeks after regular use, and up to 30-90 days after chronic heavy use. Blood, saliva, and hair tests have different detection windows.

Is CBD addictive?

CBD (cannabidiol) is not considered addictive. A 2017 WHO report concluded that CBD exhibits no effects indicative of abuse or dependence potential. CBD does not produce intoxication and has a favorable safety profile.

References

  1. National Institute on Drug Abuse. (2024). Cannabis (Marijuana) DrugFacts.
  2. Substance Abuse and Mental Health Services Administration. (2023). Key Substance Use and Mental Health Indicators.
  3. American Psychiatric Association. (2022). Diagnostic and Statistical Manual of Mental Disorders (DSM-5-TR).
  4. Volkow, N.D., et al. (2014). Adverse Health Effects of Marijuana Use. NEJM.
  5. ElSohly, M.A., et al. (2016). Changes in Cannabis Potency Over the Last 2 Decades. Biological Psychiatry.

This article was reviewed by the Valley Spring Recovery Center Editorial Team. For more information about cannabis use disorder treatment, call (201) 781-8812 or visit our admissions page.

Valley Spring Recovery Center — Evidence-based addiction treatment in Norwood, New Jersey.