What are the potential interactions between Strattera (atomoxetine) and marijuana use in patients with Attention Deficit Hyperactivity Disorder (ADHD), particularly those with a history of substance use disorders or other psychiatric conditions?

Strattera and Marijuana: Avoid Concurrent Use

Patients taking Strattera (atomoxetine) for ADHD should avoid marijuana use, as cannabis significantly worsens the core neurocognitive deficits that atomoxetine is intended to treat—including attention, memory, decision-making, and processing speed—and increases psychiatric risks that are already elevated in ADHD populations. 1

Why This Combination Is Problematic

Cannabis Directly Undermines ADHD Treatment Goals

• Cannabis causes the exact neurocognitive impairments that atomoxetine treats: deficits in attention, learning, memory, planning, and psychomotor speed—all of which are already compromised in ADHD patients 1
• Adolescent cannabis use produces structural brain changes including altered gray matter volume, cortical thickness, and prefrontal cortex connectivity, with deficits in episodic memory, decision-making, attention, and processing speed 2
• These neural changes occur more rapidly in adolescents than adults, and many cannabis-related structural changes are unique to this age group 2
• Earlier age of cannabis onset exacerbates these adverse neurocognitive effects 1

Psychiatric Risk Amplification

• Cannabis increases risk for psychiatric comorbidities commonly seen with ADHD: anxiety, depression, and worsening of ADHD symptoms themselves 1
• Cannabis use may exacerbate psychiatric disorders in vulnerable individuals, with 10% of adults with chronic cannabis use developing cannabis use disorder 2
• Heightened risk for transition to schizophrenia and psychosis has been attributed to cannabis-related alterations in glutamate and dopamine signaling 2
• The developing adolescent brain shows increased susceptibility to cannabis effects via inhibiting GABAergic inhibitory action on glutamatergic neurons 2

Evidence Shows Cannabis Does Not Help ADHD

• A scoping review of 39 studies found that most studies indicated cannabis worsened or had no effect on ADHD symptoms, despite patient reports of subjective improvement 3
• The only randomized placebo-controlled trial measuring cannabis effects on ADHD found no significant effect on the primary outcome (QbTest: Est = -0.17,95% CI -0.40 to 0.07, p = 0.16) 3
• Cannabis is not recommended for people with ADHD based on current evidence 3

Clinical Management Algorithm

If Patient Is Currently Using Cannabis:

1. Screen for cannabis use in all ADHD patients, particularly adolescents, as cannabis use is more prevalent in ADHD populations than the general population 4

2. Assess baseline ADHD symptoms off cannabis before initiating or optimizing atomoxetine treatment, as cannabis confounds accurate assessment of ADHD symptom severity 4

3. Educate on harm reduction if cannabis use continues 1:

   • Avoid high THC-content products
   • Avoid synthetic cannabinoids
   • Choose non-inhalation routes (edibles have slower onset, reducing risk of overconsumption) 2
   • Limit frequency of use (heavy use defined as >4 times per week for over a year increases risk of cannabinoid hyperemesis syndrome) 2
   • Never drive while impaired (cannabis users are more than twice as likely to be involved in motor vehicle crashes) 2

4. Monitor for worsening outcomes 1:

   • ADHD symptom deterioration
   • Mood changes (depression, anxiety)
   • Cognitive impairment
   • Development of cannabis use disorder (17% incidence within 12 weeks in medical cannabis card holders vs 9% in controls) 2

Atomoxetine-Specific Considerations:

• Atomoxetine remains a reasonable choice in patients with substance use concerns, as it has negligible abuse potential and is not a controlled substance 5, 6
• Atomoxetine has been studied systematically in subjects with ADHD and comorbid substance use disorders 5
• The median time to response is 3.7 weeks, with probability of symptom improvement continuing up to 52 weeks 5
• Do not combine atomoxetine with MAO inhibitors (absolute contraindication) or use in active psychosis 7

Common Pitfalls to Avoid

• Do not rely on patient self-report that cannabis "helps" their ADHD—subjective improvement does not correlate with objective measures, and most evidence shows worsening or no effect 3, 8
• Do not assume cannabis is "safer" than stimulants—the neurocognitive and psychiatric risks in ADHD populations are substantial and well-documented 1, 2
• Do not ignore the developmental vulnerability of adolescent and young adult brains to cannabis effects, particularly in those with ADHD who already have neurocognitive challenges 1
• Be aware that long-term daily cannabis users may experience withdrawal symptoms (irritability, restlessness, anxiety, sleep disturbances, appetite changes, abdominal pain) lasting up to 14 days after cessation 2