The purpose of this study is to evaluate the effects of a novel psychological intervention for adult ADHD through a randomized controlled trial. Participants will be randomized to receive either a face-to-face manualized short psychological intervention, SAINT, or corresponding self-help material with limited access to therapist support. The main objective is to evaluate whether SAINT will show better outcomes on measures of ADHD-related symptoms, everyday function, and quality-of-life measures, when compared to the self-help material, and if any possible differences in outcomes are related to better treatment adherence in SAINT.

ADHD is associated with deficiencies in short-term memory and executive function, negatively affecting patients' abilities to organize, schedule, multitask, follow through on instructions and finish jobs. This leads to uneven performance and possibly chronic underperformance in relation to actual intellectual resources. Psychiatric comorbidity is common for patients with ADHD, with 70-80% of adult patients meeting the criteria for at least one more clinical diagnosis. ADHD is also associated with sensation seeking and reckless behavior, including substance use and criminal activity.

Despite an increase in demand for assessment and treatment of ADHD among adults, access to evidence-based treatment is limited. In Sweden, most adult patients with ADHD are only offered pharmacological treatment. Pharmacological treatment, while in many cases effective, does not meet the demands of all patients, with 20-50% of patients not experiencing enough initial effect and/or excessive side-effects. Pharmacological treatment of ADHD also shows problems with long-term adherence, with approximately half of patients terminating treatment within the first two years, regardless of initial effect. Research on psychological treatment for adult ADHD is limited, though studies on behavioral treatment, including short-term therapies based on cognitive behavior therapy (CBT) and dialectic behavior therapy (DBT), have shown promising results.

This project, dubbed Short ADHD Intervention (SAINT), is based on previous research and pilot-studies of psychological treatments for adult ADHD. An existing treatment manual, based on CBT and DBT practices, will be fitted into a five-session, intensive face-to-face behavioral intervention, with a booster session at a one-month follow-up. The intervention will be compared to an equally long, active comparative control, consisting of self-help material and limited therapist support via Internet. Approximately 80 participants will be recruited at outpatient clinics in Stockholm. The participants will be randomized to receive either SAINT or the self-help material and limited therapist support.

Inclusion Criteria:

• Swedish citizen
• Clinical Diagnosis of ADHD according to DSM-IV or DSM-5.
• Score of 17 or higher on the Adult ADHD Self Report Scale (ASRS v1.1), on any one of the two subscales.
• Not medically treated for ADHD symptoms throughout the study period, or medically treated with central stimulants or comparable substances since at least one month, with no significant changes in dosage and no anticipated significant changes in dosage.
• No change in any other medical treatment for psychiatric symptoms.
• Ability to participate in treatment during the study period.
• Abstinence from illegal substance use for at least three months.
• Access to and ability to use Internet and mobile phone during the study period.
• Ability to understand Swedish in speech and writing, and ability to fill-out forms online.

Exclusion Criteria:

• Clinical diagnosis of substance use disorder within three months prior to screening. Earlier episodic use of illegal substances is not excluding.
• Co-existing psychiatric condition or disorder expected to render the participant unable to follow-through the study processes.
• IQ ≤85 according to a prior neuropsychological assessment.
• Suicidality assessed at the first assessment interview.
• Organic brain syndrome.
• Autism spectrum disorder (ASD) where function is deemed too low for the treatment to be carried out, defined as ASD level 2 and level 3 according to DSM-5 and/or ASD with accompanying intellectual impairment and/or accompanying language impairment.
• Severe depression, defined as >34 on the MADRS-S or at a clinical assessment.
• Other current psychological treatment for ADHD or prior participation in treatment deemed to interfere with the study design.
• Limited or very limited self-rated recognition of problems regarding impulse control and/or emotional instability, in combination with low self-rated impairment, on a tailor-made measure.