We carried out a systematic search for research reviews, and clinical guidance, on the topic of antidepressants as a treatment for people on the autism spectrum in September 2016.
We identified numerous peer-reviewed scientific reviews on the topic of medications for autism but only four of these looked specifically at antidepressants. Of these, one review (Hurwitz et al, 2012) looked only at tricyclic and tricyclic-like antidepressants and three reviews (Posey et al, 2006; West et al, 2009; Williams et al, 2013) looked only at selective serotonin reuptake inhibitors (SSRIs).
We were unable to find any reviews or studies which looked only at monoamine oxidase inhibitors (MAOIs), only at serotonin-noradrenaline reuptake inhibitors (SNRIs) or only at noradrenaline and specific serotonergic antidepressants (NASSAs).
We also examined the clinical guidance published by The National Institute of Health and Care Excellence (NICE) and other organisations.
According to the National Institute of Health and Care Excellence (2013), which looked at a range of antidepressants
“There was .... no evidence for a significant positive treatment effect of antidepressant drugs on overall autistic behaviours. However, there was evidence for a number of significant adverse events associated with antidepressants.”
“Using [our] expert knowledge and opinion, [we] concluded that antidepressants should not be used to target core features of autism in children and young people.”
According to Hurwitz et al (2012), who looked at tricylics
“A limited sample of TCAs have shown small positive effects in children and adolescents with ASD, but the strength of this evidence is negatively impacted upon by the inconsistent findings between studies, the small sample sizes of the studies and their unclear risk of bias, making clear recommendations impossible at this time.”
“Clinicians considering the use of TCAs in ASD need to be aware of the limited and conflicting evidence of effect and the side effect profile of TCAs when discussing this treatment option with patients with ASD and their carers. More research is required before TCAs can be recommended for use in ASD”
According to Williams et al. (2013), who looked at SSRIs
“There is no evidence that selective serotonin reuptake inhibitors (SSRIs) are effective as a treatment for children with autism. In fact, there is emerging evidence that they are not effective and can cause harm.
“For adults, small positive effects have been seen with fewer side effects reported with fluoxetine and fluvoxamine, but the possible risk of bias and small sample size of the trials mean there is not strong evidence to support these treatments. A small study of citalopram in adults with high levels of repetitive behaviours has shown no positive effects.”
“Decisions about the use of SSRIs for established clinical indications that may co-occur with autism, such as obsessive-compulsive disorder and depression, and anxiety (in the case of adults), should be made on a case-by-case basis.”
According to West et al (2009), who looked at SSRIs
“This review suggests that SSRIs are somewhat effective in treating overall autism severity and disruptive and repetitive symptoms, but treatment is often accompanied by side effects. Autistic children seem to have increased side effects to minimal doses of medication when compared to normally developing peers. The most frequently cited side effects of SSRI treatment include behavioral activation (hyperactivity and agitation), aggression, and suicidal ideation.”
“The lack of controlled, randomized double-blind studies of the majority of serotonin modulating drugs severely restricts the ability to draw conclusions about efficacy and safety of SSRIs for children with autism. Most of the studies retrieved were open-label observational studies or retrospective chart reviews and case reports of small cohorts of patients from a single clinical facility. Such studies provide valuable exploratory information but have inherent limitations.
According to Posey et al (2006), who looked at SSRIs
“To date, placebo controlled studies of SSRIs have involved only fluvoxamine (in children and adults) and fluoxetine (in children). Open-label and retrospective studies of all other SSRIs in PDDs have also been published that suggest effectiveness. Despite these positive reports, there continues to be questions about the tolerability and appropriate dosing of SSRIs in children with PDDs. Because of the limited number of placebo-controlled studies, definitive conclusions about the role SSRIs should play in the clinical treatment of children with PDDs cannot be drawn.”