Autistic individuals may experience these challenges with forming connections due to anxiety or depression, which they are more likely to experience, and as a result isolate themselves.Other behavioral characteristics include abnormal responses to sensations (such as sights, sounds, touch, taste and smell) and problems keeping a consistent speech rhythm. The latter problem influences an individuals social skills, leading to potential problems in how they are understood by communication partners. Behavioral characteristics displayed by autistic people typically influence development, language, and social competence. Behavioral characteristics of autistic people can be observed as perceptual disturbances, disturbances of development rate, relating, speech and language, and motility.The second core symptom of autism spectrum is a pattern of restricted and repetitive behaviors, activities, and interests. In order to be diagnosed with ASD under DSM-5 or DSM-5-TR, a person must have at least two of the following behaviors:
Repetitive behaviors – Repetitive behaviors such as rocking, hand flapping, finger flicking, head banging, or repeating phrases or sounds. These behaviors may occur constantly or only when the person gets stressed, anxious or upset. Resistance to change – A strict adherence to routines such as eating certain foods in a specific order, or taking the same path to school every day. The child may have a meltdown if there is any change or disruption to their routine. Restricted interests – An excessive interest in a particular activity, topic, or hobby, and devoting all their attention to it. For example, young children might completely focus on things that spin and ignore everything else.
There is some emerging data that show positive effects of aripiprazole and risperidone on restricted and repetitive behaviors (i.e., stimming; e.g., flapping, twisting, complex whole-body movements),  but due to the small sample size and different focus of these studies and the concerns about its side effects, antipsychotics are not recommended as primary treatment of RRBs. SSRI antidepressants, such as fluoxetine and fluvoxamine, have been shown to be effective in reducing repetitive and ritualistic behaviors, while the stimulant medication methylphenidate is beneficial for some children with co-morbid inattentiveness or hyperactivity. There is scant reliable research about the effectiveness or safety of drug treatments for adolescents and adults with ASD. No known medication relieves autisms core symptoms of social and communication impairments. Alternative medicine
A multitude of researched alternative therapies have also been implemented. Many have resulted in harm to autistic people. A 2020 systematic review on adults with autism has provided emerging evidence for decreasing stress, anxiety, ruminating thoughts, anger, and aggression through mindfulness-based interventions for improving mental health.Although popularly used as an alternative treatment for autistic people, as of 2018 there is no good evidence to recommend a gluten- and casein-free diet as a standard treatment. A 2018 review concluded that it may be a therapeutic option for specific groups of children with autism, such as those with known food intolerances or allergies, or with food intolerance markers. The authors analyzed the prospective trials conducted to date that studied the efficacy of the gluten- and casein-free diet in children with ASD (4 in total).