Main Research Findings

Several recent studies have reported the benefits of fenfluramine for the symptomatic treatment of infantile autism. 1 conducted a double-blind, placebo-controlled cross-over study to evaluate the untoward effects of fenfluramine in 12 children with autism. The study found that during the initial two weeks of active drug treatment, listlessness, food refusal, and stomach upset were frequently observed. A different pattern of untoward effects was seen in the final 14 weeks of treatment, including irritability, agitation, and crying along with continued food refusal. The subjects lost 2.1% of their body weight during the active drug phase but gained weight back during the subsequent placebo phase.

Previous studies have demonstrated the effectiveness of the self-help manual My Metacognitive Training (myMCT) for patients with primary OCD. 2 examined the efficacy of myMCT in a mixed sample of 80 Italian-speaking individuals with OCD and/or depression. The study found that participants in the myMCT condition showed significant symptom improvement on the Beck Depression Inventory-II scale compared to the control group. The most prevalent adverse effects were feeling pressured by the suggested exercises or feeling bad due to not performing the exercises correctly. The study concluded that myMCT is an effective program for patients with OCD as well as those with depressive symptoms in an Italian-speaking population.

Reasons for Side Effects

Fenfluramine is a drug that inhibits serotonin reuptake, thereby increasing serotonin levels. Serotonin is a neurotransmitter involved in mood, appetite, sleep, learning, and memory. Abnormal serotonin levels are known to be associated with mental illnesses such as mood disorders, anxiety disorders, and eating disorders. The side effects of fenfluramine are thought to be caused by the increase in serotonin levels.

Common Side Effects

Listlessness

Frequently observed in the initial two weeks of fenfluramine treatment. 1

Food Refusal

Frequently observed in the initial two weeks of fenfluramine treatment. 1

Stomach Upset

Frequently observed in the initial two weeks of fenfluramine treatment. 1

Irritability

Observed in the final 14 weeks of fenfluramine treatment. 1

Agitation

Observed in the final 14 weeks of fenfluramine treatment. 1

Crying

Observed in the final 14 weeks of fenfluramine treatment. 1

Weight Loss

Subjects lost 2.1% of their body weight during the active drug phase. 1

Weight Gain

Subjects gained weight back during the subsequent placebo phase. 1

Feeling Pressured by the Suggested Exercises

The most prevalent adverse effect of myMCT was feeling pressured by the suggested exercises. 2

Feeling Bad Due to Not Performing the Exercises Correctly

The most prevalent adverse effect of myMCT was feeling bad due to not performing the exercises correctly. 2

Side Effects Management

Listlessness, Food Refusal, Stomach Upset

These side effects were frequently observed during the initial two weeks of fenfluramine treatment. If these side effects are mild, they usually subside over time. However, if these side effects are severe or persist for a long time, consult your doctor.

Irritability, Agitation, Crying

These side effects were observed in the final 14 weeks of fenfluramine treatment. If these side effects are mild, they usually subside over time. However, if these side effects are severe or persist for a long time, consult your doctor.

Weight Loss

Subjects lost 2.1% of their body weight during the active drug phase. If there is significant weight loss, consult your doctor.

Weight Gain

Subjects gained weight back during the subsequent placebo phase. If there is significant weight gain, consult your doctor.

Feeling Pressured by the Suggested Exercises

The most prevalent adverse effect of myMCT was feeling pressured by the suggested exercises. Before starting myMCT, you can adjust the amount of exercise or change the content of the exercise to suit your situation. Also, if you feel pressured by the exercise, stop immediately and consult your doctor.

Feeling Bad Due to Not Performing the Exercises Correctly

The most prevalent adverse effect of myMCT was feeling bad due to not performing the exercises correctly. Before starting myMCT, you can adjust the amount of exercise or change the content of the exercise to suit your situation. Also, if you feel bad because you couldn't perform the exercises correctly, stop immediately and consult your doctor.

Comparison between Studies

Similarities between Studies

Both studies evaluated the side effects of drugs or interventions used to treat mental disorders. Both adopted a double-blind, placebo-controlled cross-over study design, a reliable research design in medical research. Both studies used subjective assessment scales to evaluate side effects.

Differences between Studies

The two studies differed in the target disease, intervention method, evaluation method, and type of side effects. 1 evaluated the side effects of fenfluramine in children with autism, while 2 evaluated the effects and side effects of myMCT in patients with OCD and/or depressive symptoms. Also, 1 used detailed daily records kept by parents to evaluate side effects, whereas 2 used a newly developed self-reported scale.

Real-Life Application Considerations

Drugs and interventions used to treat mental illnesses, such as fenfluramine and myMCT, are not effective for everyone. They also carry the risk of side effects. Therefore, it is important to consult your doctor before using these drugs or interventions and choose the appropriate treatment method for your situation. In particular, in the case of fenfluramine, caution is necessary as large-scale studies on its administration to children with autism have not yet been conducted. myMCT is a self-learning program, so you need to manage the exercises yourself. As a result, there is a possibility that you may feel pressured by the exercises or feel bad because you were not able to perform the exercises correctly. If you experience these side effects, stop immediately and consult your doctor.

Limitations of Current Research

The study 1 had a small sample size and used only detailed daily records kept by parents to evaluate side effects, which may introduce bias. The study 2 used a newly developed self-reported scale to evaluate side effects, and its reliability and validity may not yet have been adequately verified.

Future Research Directions

To gain a deeper understanding of the side effects of drugs and interventions used to treat mental illnesses, such as fenfluramine and myMCT, larger-scale studies are needed. Objective assessment scales should also be used to evaluate side effects. Further research is needed to elucidate the mechanisms underlying the occurrence of side effects.

Conclusion

Fenfluramine may be effective for the symptomatic treatment of infantile autism, but it has been found to have side effects such as listlessness, food refusal, and stomach upset. myMCT may be an effective program for patients with OCD and/or depressive symptoms, but it may have side effects such as feeling pressured by the exercises or feeling bad due to not performing the exercises correctly. It is important to consult your doctor before using these drugs or interventions and choose the appropriate treatment method for your situation.