Attention-deficit/hyperactivity disorder (ADHD) is characterised by a persistent and impairing pattern of inattention and/or hyperactivity/impulsivity and it is one of the most common neuropsychiatric conditions. Evidence about interventions of adults with ADHD is growing rapidly and clinicians need a reliable summary of all the best available information in order to better inform their daily practice. We searched MEDLINE, PubMed, PsycINFO and Cochrane databases until 31 May 2016 for systematic reviews about pharmacological and non-pharmacological treatments in adults with ADHD and carried out a meta-review to address clinically relevant questions. We identified a total of 40 papers. Psychostimulants—such as methylphenidate, dexamphetamine, mixed amphetamine salts and lisdexamfetamine—and non-psychostimulants—such as atomoxetine—were the most studied agents. Overall, pharmacological treatments were significantly more efficacious than placebo (standardised mean difference (SMD) 0.45, 95% CI 0.37 to 0.52), albeit less well accepted (OR 1.18, 95% CI 1.02 to 1.36) and tolerated (OR 2.29, 95% CI 1.97 to 2.66). The effects of pharmacological treatment for individuals with co-occurring ADHD and substance use disorder are still uncertain. The evidence for the efficacy and effectiveness of non-pharmacological treatments of ADHD in adults, as well as the combination of pharmacological and non-pharmacological strategies, is only preliminary. In conclusion, while available evidence addressed mainly the efficacy and tolerability of psychostimulants and non-psychostimulants for ADHD core symptoms in the short term, we still need further empirical support for the non-pharmacological and multimodal treatments. A comprehensive evidence-informed hierarchy of ADHD drugs based on their efficacy and tolerability is not yet available but it should be the next research priority in the field.