Anxiety disorders Anxiety disorders are common among children and adults with autism. Symptoms are likely affected by age, level of cognitive functioning, degree of social impairment, and autism-specific difficulties. Many anxiety disorders, such as
social anxiety disorder and
generalized anxiety disorder, are not commonly diagnosed in people with autism because such symptoms are better explained by autism itself, and it is often difficult to tell whether symptoms such as compulsive checking are part of autism or a co-occurring anxiety problem. The prevalence of anxiety disorders in children with autism has been reported to be anywhere between 11% and 84%; the wide range is likely due to differences in the ways the studies were conducted. A
systematic review summarized available evidence on interventions to reduce anxiety in school children with autism. Of the 24 studies reviewed, 22 used a
cognitive behavioral therapy (CBT) approach. The review found that CBT was moderately to highly effective at reducing anxiety in school children with autism, but that effects varied depending on whether they were reported by clinicians, parents or self-reported. CBT was found to be only moderately effective at reducing anxiety when autistic people reported the effects themselves. Treatments involving parents and one-on-one compared to group treatments were more effective.
Attention deficit hyperactivity disorder The diagnosis manual
DSM-IV did not allow the co-diagnosis of autism and
attention deficit hyperactivity disorder (ADHD). However, following years of clinical research, the
DSM-5 released in 2013 removed this prohibition of co-morbidity. Thus, individuals with autism may also have a diagnosis of ADHD, with the modifiers of a predominantly inattentive, hyperactive, combined, or not otherwise specified presentation. Clinically significant symptoms of these two conditions commonly co-occur, and children with both sets of symptoms may respond poorly to standard ADHD treatments. Individuals with autism may benefit from additional types of medications. The term
AuDHD is sometimes used for those with both autism and ADHD. There are also studies suggesting noticeable differences in presenting symptoms by gender which can complicate diagnosis, especially in adulthood.
Avoidant/restrictive food intake disorder Avoidant/restrictive food intake disorder (ARFID) is a feeding or
eating disorder in which individuals significantly limit the volume or variety of foods they consume, causing
malnutrition,
weight loss, and
psychosocial problems. A 2023 review concluded that "there is considerable overlap between ARFID and autism," finding that 8% to 55% of children diagnosed with ARFID were autistic. Unlike eating disorders such as
anorexia nervosa and
bulimia,
body image disturbance is not a root cause. Individuals with ARFID may have trouble eating due to the sensory characteristics of food (appearance, smell, texture, or taste);
executive function disregulation; fears of choking or vomiting; low appetite; or a combination of these factors.
Bipolar disorder Bipolar disorder, or manic-depression, is itself often claimed to be comorbid with a number of conditions, including autism.
Bowel disease Gastrointestinal symptoms are a common comorbidity in autistic people, even though the underlying mechanisms are largely unknown. The most common gastrointestinal symptoms reported by proprietary tool developed and administered by Mayer, Padua, and Tillisch (2014) are abdominal pain, constipation, diarrhea and bloating, reported in at least 25 percent of participants.
Depression Major depressive disorder has been shown by several studies to be one of the most common comorbid conditions in those who are autistic. In addition, the presentation of depression in autism can depend on the level of cognitive functioning in the individual, with lower functioning children displaying more behavioral issues and higher functioning children displaying more traditional depressive symptoms. with approximately 40% of autistic adults having depression.
Developmental coordination disorder (dyspraxia) The initial accounts of
Asperger syndrome They may show problems with
proprioception (sensation of body position) on measures of developmental coordination disorder, balance,
tandem gait, and finger-thumb apposition.
Epilepsy Autism is also associated with
epilepsy, with variations in risk of epilepsy due to age, cognitive level, and type of language disorder. One in four autistic children develop
seizures, often starting either in early childhood or adolescence. Seizures, caused by abnormal electrical activity in the brain, can produce a temporary loss of consciousness (a "blackout"), a body convulsion, unusual movements, or staring spells. Sometimes a contributing factor is a lack of sleep or a high fever. An
EEG can help confirm the seizure's presence. Typically, onset of epilepsy occurs before age five or during puberty, and is more common in females and individuals who also have a comorbid
intellectual disability.
Fetal alcohol spectrum disorder Fetal alcohol spectrum disorders (FASD) are a group of conditions that can occur in a person who is exposed to
alcohol during
gestation. Evidence on the link between FASD and autism is limited. Although results from studies are mixed, it is estimated that 2.6% of children with an FASD are autistic as well, a rate almost two times higher than that reported in the general US population.
Gender dysphoria Gender dysphoria is a diagnosis given to
transgender people who experience discomfort related to their gender identity. Autistic people are more likely to experience gender dysphoria. Around 20% of gender identity clinic-assessed individuals reported characteristics of autism.
Hypermobility spectrum disorder and Ehlers–Danlos syndromes Studies have confirmed a link between hereditary connective tissue disorders such as
Ehlers-Danlos syndromes (EDS) and
hypermobility spectrum disorder (HSD) with autism, as a comorbidity and a co-occurrence within the same families.
Intellectual disability The fraction of autistic individuals who also meet criteria for intellectual disability has been reported as anywhere from 25% to 70%. This wide variation illustrates the difficulty of assessing intelligence in autistic individuals.
Learning disabilities are also highly comorbid in individuals with autism. Approximately 25–75% of individuals with autism also have some degree of learning disability, although the types of learning disability vary depending on the specific strengths and weaknesses of the individual. A 2006 review questioned the common assumption that most children with autism have an intellectual disability. The CDC states that based on information from 11 reporting states 46% of people with autism have above 85 IQ.
Mitochondrial diseases The central player in
bioenergetics is the
mitochondrion. Mitochondria produce about 90% of cellular energy, regulate cellular redox status, produce
ROS, maintain
homeostasis, synthesize and degrade high-energy biochemical intermediates, and regulate
cell death through activation of the
mitochondrial permeability transition pore (mtPTP). When they fail, less and less energy is generated within the cell. Cell injury and even cell death follow. If this process is repeated throughout the body, whole organ systems begin to fail.
Mitochondrial diseases are a heterogeneous group of disorders that can affect multiple organs with varying severity. Symptoms may be acute or chronic with intermittent decompensation. Neurological manifestations include
encephalopathy,
stroke, cognitive regression,
seizures,
cardiopathies (cardiac conduction defects,
hypertensive heart disease,
cardiomyopathy, etc...),
diabetes,
visual and
hearing loss,
organ failure,
neuropathic pain and
peripheral neuropathy. Mitochondrial disease is estimated to affect less than 0.1% of the general population. Approximately 5% of autistic children meet the criteria for classical mitochondrial dysfunction. It is unclear why this mitochondrial disease occurs, considering that only 23% of children with both autism and mitochondrial disease present with
mitochondrial DNA abnormalities. NF-1 is a complex multi-system human disorder caused by the mutation of a gene on
chromosome 17 that is responsible for production of a protein, called
neurofibromin 1, which is needed for normal function in many human cell types. NF-1 causes tumors along the nervous system which can grow anywhere on the body. NF-1 is one of the most common genetic disorders and is not limited to any person's race or sex. NF-1 is an
autosomal dominant disorder, which means that mutation or deletion of one copy (or allele) of the NF-1 gene is sufficient for the development of NF-1, although presentation varies widely and is often different even between relatives affected by NF-1.
Neuroinflammation and immune disorders The role of the
immune system and neuroinflammation in the development of autism is controversial. A 2013 review also found evidence of
microglial activation and increased
cytokine production in
postmortem brain samples from people with autism.
Obsessive–compulsive disorder Obsessive–compulsive disorder (OCD) is diagnosed by the presence of obsessions (unwanted, intrusive thoughts, images or urges) that cause significant discomfort and/or compulsions (repetitive mental or behavioral acts) that a person feels driven to do to decrease their discomfort and/or get rid of the obsession. The presentation of compulsions in OCD can overlap with the restricted and repetitive behavior seen in autism. OCD individuals often avoid thinking about their obsessions, while autistic individuals may hyper-fixate on an obsession and not find their intrusive thoughts distressing. An estimated 24% of autistic adults have OCD. The
National Institute for Health and Care Excellence (NICE) recommends two main therapies for OCD: cognitive behavioral therapy (CBT) and/or Exposure and Response Prevention (ERP) therapy to help break down problems into their separate parts such as thoughts, physical feelings and actions.
Psychosis and schizophrenia Childhood-onset schizophrenia is preceded by childhood autism in almost half of cases, and an increasing number of similarities are being discovered between the two conditions.
Schizoid personality disorder Several studies have reported an overlap, confusion or comorbidity with
Asperger syndrome (which has been combined with autism and no longer appears as a diagnostic label in the DSM-5). Asperger syndrome was at one time called "
schizoid disorder of childhood".
Eugen Bleuler coined the term "autism" to describe withdrawal to an internal fantasy, against which any influence from outside becomes an intolerable disturbance. Although the cause for this comorbidity is not yet certain, genetic evidence for a spectrum between
cluster A personality disorders/
schizophrenia and autism has been found.
Self-injury and suicide Self-injurious behaviors are relatively common in autistic people, and can include head-banging, self-cutting, self-biting, and hair-pulling. Some of these can result in serious injury or death. Theories about the cause of self-injurious behavior in children with developmental delay, including autistic children, include: • Frequency or continuation of self-injurious behavior can be influenced by environmental factors (e.g., reward in return for halting self-injurious behavior). This theory does not apply to younger children with autism. There is some evidence that frequency of self-injurious behavior can be reduced by removing or modifying environmental factors that reinforce the behavior. Rates of suicidality vary significantly depending upon what is being measured. and a third of all autistic people have experienced
suicidal ideation at some point. Rates of suicidal ideation are the same for people formally diagnosed with autism and people who have typical intelligence and are believed to have autism but have not been diagnosed. Less than 10% of autistic youth have attempted suicide,
Sensory processing disorder (SPD) is comorbid with autism, with comorbidity rates of 42–88%. With or without meeting the standards of SPD, about 90% of autistic individuals have some type of atypical sensory experiences, described as both hyper- and hypo-reactivity.
Sleep disorders Sleep disorders are commonly reported by parents of individuals with autism, including late sleep onset, early morning awakening, and poor sleep maintenance; Unlike general pediatric
insomnia, which has its roots in behavior, sleep disorders in individuals with autism are comorbid with other neurobiological, medical, and psychiatric issues. Studies have found abnormalities in the physiology of melatonin and circadian rhythm in people with autism.
Strabismus According to several studies, there is a high prevalence of
strabismus in autistic individuals, with rates 3–10 times that of the general population.
Tourette syndrome The prevalence of
Tourette syndrome among individuals who are autistic is estimated to be 6.5%, higher than the 2% to 3% prevalence for the general population. Several hypotheses for this association have been advanced, including common genetic factors and
dopamine,
glutamate or
serotonin abnormalities. Studies have reported that between 25% and 61% of individuals with tuberous sclerosis meet the diagnostic criteria for autism with an even higher proportion showing features of a broader
pervasive developmental disorder.
Other mental disorders Phobias and other
psychopathological disorders have often been described along with autism but this has not been assessed systematically. ==Notes==