Anxiety disorders commonly begin during adolescence, and are characterized by deficits in the ability to inhibit or extinguish pathological fear. Recent research has provided new understanding of how fear is learned and can be regulated in the adolescent brain, and how the endocannabinoid system shapes these processes; however, these advances have not yet translated into improved therapeutic outcomes for adolescents with anxiety. This study will test whether a behavioral intervention, acute exercise, can help to improve fear regulation by enhancing brain activity and endocannabinoid signaling. This line of research may ultimately lead to more effect treatments for adolescent anxiety, and to new preventive strategies for at-risk youth.

Inclusion Criteria:

1. Provision of signed and dated informed consent form
2. Stated willingness to comply with all study procedures and available for the duration of the study
3. 14-17 years of age upon enrollment
4. Right-handed
5. In good general health as evidenced by medical history
6. Adolescent and parent/guardian are English-speaking, as study assessments are in English
7. Availability of a parent or legal guardian who is willing to provide consent and attend all study visits

Exclusion Criteria:

1. Traumatic brain injury with ongoing symptoms
2. Sensory (e.g., hearing) or physical (e.g., motor, balance) impairment or significant developmental delay
3. MRI participants: MRI contraindication (e.g., braces, implants, claustrophobia)
4. Any condition that would contraindicate blood draws (e.g., hemophilia, sickle cell)
5. Past or current diagnosis or presence of likely neurological disorder (e.g., epilepsy), psychotic disorder (e.g., schizophrenia, schizoaffective disorder), or bipolar disorder
6. Severe/unstable medical condition (e.g., diabetes, rheumatoid arthritis)
7. Current (past 1-month) use of cannabis or cannabinoid products including CBD unless willing to stop for at least 4 weeks prior to entering the study
8. Currently pregnant, lactating, or positive pregnancy test at screening visit
9. Current homicidal thoughts or suicide attempt in the past year
10. Current suicidal thoughts requiring immediate intervention
11. Concurrent use (past 6 weeks) of oral contraceptives
12. Diagnosed or probable substance use disorder (past 1-month)
13. Positive drug test at baseline visit (e.g., THC, cocaine)
14. Moderate/severe drug or alcohol use in the past 8 weeks
15. Current or recent (past 1-month) COVID-19 diagnosis or febrile illness
16. Treatment with investigational drug or intervention (past 1-month)
17. Current smoker, vaper, or tobacco or nicotine use (past 1-month)
18. Ongoing exposure to abuse

Females must not be pregnant, breastfeeding, or postpartum less than 6 months