SNAPPER is a randomised controlled trial to evaluate the clinical and cost-effectiveness of stimulant (Lisdexamfetamine) compared with non-stimulant (Atomoxetine) medication for adults with attention defecit/hyperactivity disorder (ADHD) and history of psychosis or bipolar disorder.

SNAPPER LOGO FINAL_small

Latest SNAPPER Trial Update: 07-April-2025

Total number of participants randomised: 100

The SNAPPER Trial is actively recruiting new participants. Trial recruitment is ancitipated to end in May 2026. If you think you are eligible to take part, please contact your nearest participating NHS Trust. Contact details for the Trust can be found in the Recruiting Centres section of the Recruitment page.

SNAPPER 100pts image

Design

SNAPPER is a pragmatic, observer-blind, national, multi-centre, 2-arm, parallel group randomised controlled trial. 

 

Aim of the Study


The aim of the main study is to evaluate in adults with ADHD and a history of psychosis or bipolar whether stimulant (Lisdexamfetamine) vs. non-stimulant (Atomoxetine) medicated reduces ADHD symptom severity at 6 months.

Setting

Patients recruited from NHS secondary and tertiary community and inpatient mental health services, and research clinics across the UK.

Target Population

People aged 18 years and over. Existing or new diagnoses of ADHD and psychosis or bipolar disorder confirmed/ re-confirmed as part of study diagnostic screening assessments in people who are not currently (or within the last month) on medication for ADHD.

Intervention

People consented to take part will be randomised to receive either:

  • Lisdexamfetamine (stimulant) initiated at 30mg once daily, and increased to a maximum of 70mg once daily for 6 months.

Or

  • Atomoxetine (non-stimulant) initiated at 40mg daily, and increased to a maximum of 100mg daily for 6 months.

Measurement of outcomes

Primary outcome measure:

  • ADHD symptoms at 6 months post-randomisation, as measured by the Conners Adult ADHD Rating Scale-Observer (CAARS-O) total score.


Secondary outcome measures:

  • Longitudinal Interval Follow-up Evaluation (LIFE)
  • Positive and Negative Symptoms Scale (PANSS)
  • Difficulties in Emotion Regulation Scale (DERS-16)
  • Wender-Reimherr Adult Attention Definit Disorder Scale-Interview (WRAADS-Interview)
  • Adult ADHD QOL Measure (AADHD QOL)
  • Quality of life: EQ-5D-5L and ICEpop CAPability measure for Adults (ICECAP-A)
  • Functioning Assessment Short Test (FAST)
  • Drug Abuse Screening Test (DAST)
  • Alcohol Use Disorders Identification Test (AUDIT)
  • Medication Adherence Rating Scale (MARS)
  • Compliance self-report
  • Healthcare Resource Usage measured by the modified Client Service Recipient Inventory (CSRI).

 

More information...

Chief Investigator

Prof Steven Marwaha, Professor of Psychiatry. Institute for Mental Health, School of Psychology, University of Birmingham

Deputy Trials Management Team Leader

Shrushma Loi. Birmingham Clinical Trials Unit, University of Birmingham

Funder 

National Institute of Health Research (HTA programme ref. NIHR 129817)

Sponsor 

University of Birmingham

REC 

Central Bristol

EudraCT no. 

2021-000302-21

ISRCTN

https://doi.org/10.1186/ISRCTN79796233

CPMS ID

49907