What would be the best dosage of effexor (venlafaxine) for adhd ? 75 or 150 mg?

Though a small study: showed promise for Venlafaxine to have a 70% chance of reducing ADHD symptoms in adults, it's not FDA- approved for that use. It is prescribed to some adults with Anxiety Disorders & comorbid ADHD. Venlafaxine affects serotonin in low doses (75 mg/day), serotonin & norepinephrine at moderate doses (150-225 mg/day) & serotonin, norepinephrine, & dopamine in high doses (300- 375 mg/day)