Excessive Masturbation Successfully Treated with Fluoxetine in an Adolescent with Autism Spectrum Disorder and Coexisting Depression

To the Editor:

Autism spectrum disorder (ASD) has high comorbidity rates including attention-deficit/hyperactivity disorder, depression, and anxiety disorders in childhood (Salazar et al. 2015; Tarazi et al. 2015). These comorbidities have unfavorable additive impacts on ASD sufferers' behaviors, social competence, and relationships (Salazar et al. 2015; Tarazi et al. 2015). The symptoms of these comorbid disorders can be masked by ASD symptoms themselves, especially if the child has coexisting intellectual disability (Mazzone et al. 2012). Thus, the diagnosis and treatment of comorbid psychiatric disorders can be difficult in these children.

Research has suggested that elevated depressive and anxiety symptoms can reduce the threshold for the expression of behavioral problems (Ingoldsby et al. 2006; Bubier and Drabick 2009). Inappropriate sexual behaviors are a common behavioral problem in children with ASD and may be related to coexisting psychiatric disorders (Stokes and Kaur 2005). So far, there has been a shortage of studies on the etiopathogenesis and management of inappropriate sexual behaviors in this population (Nguyen and Murphy 2001; Albertini et al. 2006). Here, we present an adolescent with ASD and comorbid depression who displayed significant benefits from fluoxetine for his depression and excessive masturbation.

Case Report

A 16-year-old boy with ASD and intellectual disability was referred to our clinic for an increase in his aggressive and self-destructive behaviors and irritability during the past 2 months. In addition, his parents describe crying episodes that lasted for about 20 minutes almost every day and excessive masturbation for 2 months (for masturbation, Clinical Global Impressions-Severity subscale = 5). He had been using aripiprazole for about 5 years due to irritability. At first, haloperidol was added to his treatment for 1 month; however, no improvement was observed. When a more detailed history was taken, a decrease in activity level was detected while the patient did not show behavioral problems during the day. The clinical picture was regarded as depression, haloperidol was terminated and fluoxetine 20 mg/day was started. His masturbatory behavior decreased markedly after the first week of the treatment, and did not recur during the patient's 3 months follow-up (Clinical Global Impressions-Improvement subscale = 2). His other symptoms, including irritability, aggression, low activity level, and self-destructive behaviors also diminished significantly.

Discussion

It seems that fluoxetine treatment is responsible for the improvement of excessive masturbatory behavior in the present case. We speculate that, in the presence of depression, the patient might be less able to control his sexual drives, and treatment of his depressive symptoms might help decrease his excessive masturbation. The improvement in self-organizing skills due to antidepressant effect of fluoxetine might lead to alleviation in this symptom. The concurrent improvement in other symptoms of depression in this case supports this hypothesis. However, it is possible that the improvement of excessive masturbation might simply be a result of the direct effect of fluoxetine on sexual functions. Selective serotonin receptor inhibitors (SSRIs) negatively influenced all components of sexual functions such as sexual desire, erection, and orgasm (Corona et al. 2009). Accordingly, the 5-HT-induced decrease in sexual function may be caused by central effects and direct penile effect of serotonin (Angulo et al. 2001; Ferguson 2001).

Fluoxetine has been reported to be effective for compulsive masturbation in a patient with schizophrenia (Kornreich et al. 1995). However, no data were available about the effectiveness of fluoxetine or other SSRIs on this behavior in cases with ASD. We acknowledge that fluoxetine provided a marked benefit in an adolescent with excessive masturbation diagnosed with ASD and coexisting depression. Further studies are needed to expand the possible applications of fluoxetine in these patients.