ISRCTN15984604.

Study name	Sertraline for anxiety in adults with a diagnosis of autism
Methods	14‐week parallel trial of sertraline versus placebo
Participants	Inclusion criteria: "Aged ≥18 years and have a diagnosis of autism (including autism spectrum disorder/condition or other variations, Asperger syndrome, or pervasive developmental disorder); experience anxiety for which participants are willing to try treatment with medication; able to complete online or paper‐based questionnaires about things such as anxiety, other symptoms, and healthcare usage; able to provide informed consent to take part". Exclusion criteria: "currently taking medication(s) for depression and/or anxiety, or have taken them in the past 8 weeks, or are using St John’s Wort; have a moderate or severe learning disability which means they may not be able to provide informed consent and/or understand and complete the study questionnaires; have/had other mental health conditions such as bipolar disorder or psychosis; have epilepsy that is not well controlled; have current problematic use of alcohol or illicit drugs; have allergies to sertraline or placebo; have/had severe liver problems, bleeding disorders, some heart problems; have swallowing difficulties or are unable to take medication in capsule form; taking part in another clinical trial; or are pregnant, planning pregnancy during the study period, or breastfeeding." Location/setting: the UK and Australia Target sample size: 306 participants
Interventions	Intervention (sertraline): the first 2 weeks participants will receive 25 mg of sertraline in tablet form, increasing to 25 mg twice daily for the next 4 weeks. Dose can be increased by 50 mg every 4 weeks until the optimal dose is reached. Comparator: the first 2 weeks participants will receive 25 mg of placebo in tablet form, increasing to 25 mg twice daily for the next 4 weeks. Dose can be increased by 50 mg every 4 weeks until the optimal dose is reached.
Outcomes	Primary outcomes: AEs Secondary outcomes: health‐related QoL measured using EQ‐5D‐5L questionnaire Timing of outcome assessments: baseline, 12, 16, 24 and 52 weeks
Starting date	October 2019
Contact information	Contact name: Adam Taylor Contact details: research‐governance@bristol.ac.uk
Notes	Source of funding: National Institute for Health Research Health Technology Assessment programme (NIHR HTA) (UK) and the National Health and Medical Research Council (NHMRC) (Australia) Conflicts of interest: details not reported