(e.g., one might regain ability to focus with medication, but skills such as organizing, prioritizing and effectively communicating have taken others time to cultivate). Suggested treatment for adult ADHD is to include a combined approach of psychosocial interventions (behavioural or cognitive), medication, vocational interventions, and regular follow-up support. Medications Medications to help treat ADHD include psychostimulants and non-stimulants. Guidelines and availability of the different options available for medication may vary depending on what country the person lives in. Stimulants Stimulants have moderate-to-high effects, which have higher average effects than non-stimulant medications. For adults, amphetamines in particular are the most efficacious medications and they (along with methylphenidate) have the least adverse effects. While there is some debate about whether to treat ADHD adults with substance use disorder (SUD) with stimulants, the 2019 Updated European Consensus Statement on diagnosis and treatment of adult ADHD notes that "in SUD patients, treatment of ADHD [with stimulants] can be useful to reduce ADHD symptoms without worsening the SUD, and should not be avoided". Amphetamine and its derivatives, prototype stimulants, are available in immediate and long-acting formulations. Amphetamines act by multiple mechanisms including reuptake inhibition, displacement of transmitters from vesicles, reversal of uptake transporters and reversible MAO inhibition. Thus amphetamines actively increases the release of these neurotransmitters into the synaptic cleft. In the short term, methylphenidate, a benzylpiperidine and phenethylamine derivative stimulant medication, is well tolerated. As of a 2008 review, long-term studies had not been conducted in adults, although no serious side effects had been reported to regulatory authorities. In the UK, clinical guidelines recommend that psychostimulants are used as a first-line treatment. For people who cannot be treated with stimulants due to a substance use disorder or other contraindications, atomoxetine is the suggested first line treatment in the UK. In Canada, clinical guidelines suggest that first line treatment be methylphenidate or lisdexamfetamine. Non-stimulant medications are generally second-line treatments in Canada. Non-stimulant medications The non-stimulant atomoxetine (Strattera), may be an effective treatment for adult ADHD. Although atomoxetine has a half life similar to stimulants it exhibits delayed onset of therapeutic effects similar to antidepressants. Unlike stimulants which are generally controlled substances, atomoxetine lacks addictive potential. It is particularly effective for those with the predominantly inattentive concentration type of attention deficit due to being primarily a norepinephrine reuptake inhibitor. It is often prescribed in adults who cannot tolerate the side effects of amphetamines or methylphenidate. It