Cochrane Review: Selective serotonin reuptake inhibitors (SSRIs) for autism spectrum disorders (ASD)




Autism spectrum disorders (ASD) are characterised by abnormalities in social interaction and communication skills, as well as stereotypic behaviours and restricted activities and interests. Selective serotonin reuptake inhibitors (SSRIs) are prescribed for the treatment of co-morbidity associated with ASD such as depression, anxiety and obsessive-compulsive behaviours.


To determine if treatment with an SSRI:

1. improves the core features of autism (social interaction, communication and behavioural problems);

2. improves other non-core aspects of behaviour or function such as self-injurious behaviour;

3. improves the quality of life of children and their carers;

4. has short and long term effects on outcome;

5. causes harms.

Search strategy

We searched the Cochrane Central Register of Controlled Trials (The Cochrane Library 2009, Issue 4), MEDLINE ( December 2009), EMBASE (December 2009), CINAHL (December 2009), PsycINFO (December 2009) and ERIC (December 2009), without language restrictions.

Selection criteria

Randomised controlled trials (RCTs) of any dose of oral SSRI compared with placebo, in participants with autism spectrum disorders. Trials must have included at least one standardised outcome measure.

Data collection and analysis

Two authors independently selected and appraised studies for inclusion and risk of bias. All data were continuous. Meta-analysis, where possible, used a random-effects model.

Main results

Seven RCTs with a total of 271 participants were included. Four SSRIs were evaluated: fluoxetine (two studies), fluvoxamine (two studies), fenfluramine (two studies) and citalopram (one study). Five studies included only children and two studies included only adults. Varying inclusion criteria were used with regard to diagnostic criteria and intelligence of participants. Seventeen different outcome measures were reported. Although more than one study reported data for Clinical Global Impression (CGI) and obsessive-compulsive behaviour (OCB), different tool types or components of these outcomes were used in each study. As such, data were unsuitable for meta-analysis. One large, high quality study in children showed no evidence of positive effect of citalopram. Two small studies in adults showed positive outcomes for CGI and OCB; one study showed improvements in aggression, and another in anxiety.

Authors' conclusions

There is no evidence of effect of SSRIs in children and emerging evidence of harm. There is limited evidence of the effectiveness of SSRIs in adults from small studies in which risk of bias is unclear.

Plain Language Summary

Selective serotonin reuptake inhibitors for the treatment of autism spectrum disorders

Autism spectrum disorders (ASD) are characterised by problems with social interaction and communication, as well as repetitive behaviours and limited activities and interests. Selective serotonin reuptake inhibitors (SSRIs) are a class of antidepressants which are sometimes given to help anxiety or obsessive compulsive behaviours. We found seven trials which evaluated four SSRIs: fluoxetine, fluvoxamine, fenfluramine and citalopram. Five studies included only children and two studies included only adults. One trial enrolled 149 children, but all other trials were small. We found no trials which evaluated sertraline, paroxetine or escitalopram. There is no evidence to support the use of SSRIs to treat autism in children. There is limited evidence, which is not yet sufficiently robust, to suggest effectiveness of SSRIs in adults with autism. Treatment with an SSRI may cause side effects. Decisions about the use of SSRIs for established clinical indications that may co-occur with autism, such as obsessive compulsive disorder and depression in adults or children, and anxiety in adults, should be made on a case by case basis.