Antidepressant does not stop repetitive behaviours in autistic children

The antidepressant citalopram does not appear to reduce the occurrence of repetitive behaviours in children and teens with autism spectrum disorders, according to a report in the June issue of Archives of General Psychiatry, one of the JAMA/Archives journals.

Although the U.S. Food and Drug Administration has not approved any drugs to treat the core symptoms of autism and related disorders, medications are increasingly being used in this population, according to background information in the article. Citalopram belongs to a class of antidepressants known as selective serotonin reuptake inhibitors (SSRIs), which interfere with the way the brain regulates the neurotransmitter serotonin.

'Because of suggested similarities between repetitive behaviour in autism spectrum disorders and obsessive-compulsive disorder and the findings of serotonin system abnormalities in autism, anti-obsessional agents such as SSRIs have long been of interest,' the authors write. Repetitive behaviours in children with autism - including inflexible routines and repetitive play - tend to persevere over time and predict the endurance of an early autism diagnosis. 'Despite the relative dearth of evidence supporting their use, SSRIs are among the most frequently used medications for children with autism, partially because of their perceived safety.'

Bryan H. King, M.D., of Seattle Children's Hospital and the University of Washington, Seattle, and colleagues conducted a randomised controlled trial to determine the safety and efficacy of citalopram in children with autism spectrum disorders who had at least moderate levels of repetitive behaviour. Of 149 children age 5 to 17 (average age 9.4) with autism spectrum disorders who participated, 73 were randomly assigned to receive citalopram (at an average maximum dosage of 16.5 milligrams per day) and 76 to receive a placebo for 12 weeks. Most of the participants (82.6 percent) completed the 12-week trial.

At the end of the treatment period, there were no differences between the treatment group and the placebo group in the number of children who demonstrated improvements on scales measuring repetitive behaviour (32.9 percent vs. 34.2 percent). 'Citalopram use was significantly more likely to be associated with adverse events, particularly increased energy level, impulsiveness, decreased concentration, hyperactivity, stereotypy [mechanical repetition of the same posture or movement], diarrhoea, insomnia and dry skin or pruritis,' the authors write.

'There is growing recognition that children and adolescents with autism spectrum disorders have serious behavioural problems and psychiatric symptoms that may be appropriate targets for pharmacotherapy,' they continue. 'To date, there are few large-scale trials to guide clinical practice, so clinicians are left to address these problems with inadequate information. The results of this trial indicate that citalopram is not an effective treatment for children having autism spectrum disorders with moderate or greater repetitive behaviour. The results also highlight the urgent need for placebo-controlled trials of medications commonly used for children with autism spectrum disorders to determine whether the risks of specific drugs substantially outweigh their benefits.'