The psychosis in autism vs. the autism in psychosis

I don't know if those behaviours can only be explained by autism! said the psychiatrist. Yes, I agree. Some of the behavioural characteristics present in childhood belong to a picture of autism. But the evolution of the clinical situation seems to be more consistent with a psychosis! said the psychologist.

This brief dialogue simulated here transcribes much of the reality we observe throughout the life cycle of the autistic person. The fact that there are a significant number of other associated psychiatric disorders. But also the intersection of some of these characteristics present in different diagnoses. These are all situations which lead us to hypothesise that this may not be an autistic situation.

There is strong evidence for the existence of a high comorbidity between autism and psychosis with percentages reaching 35%. In these situations there are several significant implications for the treatment and prognosis of these people. However, the identification of comorbid psychosis in autistic people represents a complex challenge from the psychopathological point of view. Particularly in people with greater deficits in verbal communication.

Intercepting the onset of a psychotic episode in autism can be very difficult. Both conditions actually occur along a phenotypic continuum of clinical severity and in many cases psychotic symptoms are present in an attenuated form.

This proximity between psychosis and autism is not new. If historically schizophrenia and autism were considered closely related. Later, through epidemiological studies, these two conditions were reconsidered as two distinct entities, each with its own characteristics, clinical course and typical onset. However, there are a growing number of studies that focus their attention on the link between schizophrenia and autism spectrum disorders, finding significant overlaps in genetic studies, neuroimaging data, clinical signs and cognitive characteristics. Providing strong evidence for the existence of high rates of comorbidity between autism and psychosis.

According to the literature, up to 35% of autistic people can present psychotic symptoms and similarly autistic features have been reported in people with schizophrenia in a percentage ranging from 3.6 to 60%.

Precisely because of this high rate of comorbidity between autism and schizophrenia, several clinicians hypothesise the existence of a significant psychotic vulnerability in people with a neurodevelopmental disorder. In particular, observed difficulties in information processing are common in autism and may favour the risk of a transition to psychosis. The expression of core symptoms in autism can vary significantly between autistic people and may be influenced by the age of onset of this condition. In addition, symptoms, whether psychotic or autistic and which show greater attenuation, may make it even more difficult to recognise the two comorbid disorders.

Delusions are defined as "fixed beliefs that are not likely to change in the light of contradictory evidence". According to Jaspers, there are three crucial criteria for defining delusions: (1) subjective certainty, incomparable to other beliefs; (2) impermeable counter-arguments; (3) implausibility of content. Although delusions are commonly considered one of the main features of the Schizophrenia Spectrum Disorder, delusional beliefs can be recognized in different psychiatric conditions: bipolar disorder, major depressive disorder with psychotic features, neurological and medical disorders such as dementia, delirium or drug intoxication, and finally in Autism Spectrum Disorder.

The presence of delusional beliefs, suspiciousness and paranoid ideation in autistic children is reported since the first descriptions of autism and observed by different clinicians as schizophrenia-like states, borderline conditions, or severe disorders of ego development. The most common delusional beliefs in autistic people are expansive, persecutory, reference or insertion delusions and thought-stealing and "unusual idea" delusions.

In some cases, it is not easy to distinguish between "childish fantasies" and delusional beliefs. A core question being whether autistic children are able to distinguish between their subjective perceptions and reality. If we assume that the autistic condition implies an intrinsic difficulty in distinguishing between fantasy and reality, the recognition of a delirium in these people becomes a very complex psychopathological task.

Most reports of autistic children developing delusional ideas are characterised by at least two features: an average cognitive level and adequate communicative ability. These are necessary for children to express their own thoughts and for the clinician to assess children's delusions. Unfortunately, a significant number of autistic children have a major communication deficit, including mutism and cognitive deficit. In several cases, it is reported how difficult it can be for these people to describe their delusions and for clinicians to identify and classify them. For this reason, some clinicians have hypothesized to investigate the presence of delusional ideas also by means of drawings.

Autistic people have difficulties interpreting subtle social cues, probably because of a deficit in Theory of Mind. Both people with Autism Spectrum Disorder and Schizophrenia Spectrum Disorder have difficulties at this level. Autistic children may never acquire skills in theory of mind, whereas people with schizophrenia may have an intact ability to mentalise. Other clinicians suggest that even though difficulties in mentalising are clear in both autism and childhood onset schizophrenia, there are significant differences between the two clinical groups. In particular, it has been observed that high-functioning autistic people are more impaired in theory of mind when performing the faux-pas verbal test, than people with schizophrenia.

Another aspect to be taken into account at this intersection between schizophrenia and autism is hallucinations. Hallucination represents "the intimate conviction of actually perceiving a sensation for which there is no external object" while negative symptoms are represented by blunted affections, alogia, associality, anhedonia and avolition.

Hallucinations, particularly auditory ones, have been closely linked to schizophrenia and constitute one of the five key symptoms of criterion A for the diagnosis of schizophrenia according to DSM-5. Hallucinations have also been described in other psychiatric and medical conditions. Autistic people also frequently experience them. And describe and exhibit unusual patterns of sensation and that according to DSM 5, these sensory issues are a core symptom for the diagnosis of autism. However, in clinical practice, it is difficult to discern between sensory issues present in autistic people and hallucinations, with significant implications for treatment, prognosis and access to services.

Autistic people often suffer from "anomalous perceptual experiences" compared to neurotypical people. For example, perception of sounds without a visible source are commonly reported, such as hearing a train 5 to 10 minutes before it passes or hearing sounds around. These experiences refer to perceptual and hallucinatory experiences and are similar to clinical phenomena commonly associated with psychosis (voices, perceptual distortions, "out of body" experiences). Like psychotic patients, autistic people describe these experiences as intrusive and stress-causing.

A further issue is that describing appropriate sensory processing can be difficult for autistic people, mainly because of their deficits in verbal communication and their language impairment. Because concrete reading of questions may be present, investigating hallucinations in an autistic person may result in confusing answers. For example, "Do you hear voices when no one is there?" "Yes (on the radio)". In addition, people may describe their somatic complaints in unusual ways. For example, an autistic person suffering from headache described his condition by saying that his head was bleeding.

Symptoms misdiagnosed as psychotic, when considered in the context of a neurodevelopmental disorder, may be better understood as part of it rather than as a sign of a concomitant psychosis. Given the deficits in language and communication, emotional recognition, social reciprocity, stereotyped interest, theory of mind and central coherence, some clinicians claim that reliability in this clinical group can be a serious problem in distinguishing true hallucinations from imagination, memories, illusions and pseudo hallucinations.

Autistic children when reporting verbal hallucinations sometimes have difficulty recognising whether they hear their own voice or someone else's and are often unable to report the specific words or phrases that the voices may be saying. For example, one child described auditory hallucinations that sometimes told him to kill himself or others and tended to worsen when he felt under stress. Further assessment suggested that he was not truly psychotic but was having pseudo hallucinations. With therapeutic (non-pharmacological) intervention, he came to recognise that these voices were from his imagination and began to consider them less frightening until they disappeared.

Finally, it is important to address the question of negative symptoms. These are represented by blunted affect, allogia, associality, anhedonia and avolition. Unlike hallucinations and delusions, which are transdiagnostic symptoms, negative symptoms represent a central feature of psychosis and may only be present in schizophrenia or schizoaffective disorder. This is the reason why the history of negative symptoms is strongly related to the history of Schizophrenia.

Therefore, differentiating the negative symptoms of schizophrenia from autistic symptoms represents a crucial but complicated task, even for expert health professionals. For example, both social interaction and social communication deficits are frequent in patients with schizophrenia as a result of their negative symptoms. At the same time, these are considered the main clinical symptoms in autism. Moreover, the lack of emotional reciprocity in autism may be confused with the "blunted" affect in schizophrenia.

On the one hand, with regard to emotional reciprocity, it is a diagnostic criterion for autism. However, DSM 5 does not explain precisely what reciprocity means, but only provides anecdotal descriptions such as 'not actively participating in simple social play or games', 'preferring solitary activities' or 'engaging others in merely mechanical activities. Or else, blunted affect is defined as a "decrease in the expression of emotion and reactivity to events observed during spontaneous or elicited expression of emotion (facial and vocal expression and expressive gestures)" and manifests as a characteristic impoverishment of emotional expression, reactivity and feeling.

As such, to better differentiate these two concepts, it can be hypothesized that in autistic people, they may present a greater poverty in reciprocity (which may be similar to the "impairment in the expression of emotion and reactivity" of affective blunting), but also an inadequacy of reciprocity (which is more typical of autism). Moreover, also in autism restricted and repetitive behaviours can easily be misinterpreted as a symptom of schizophrenia.

The clinical course represents a key element in the differential diagnosis between autism and psychosis.

The natural course of schizophrenia is extremely heterogeneous and generally considered unpredictable. The onset of schizophrenia usually occurs between late adolescence and the mid-30s and follows a prodromal state in which social impairment, atypical interests and unusual beliefs have already occurred. Onset before adolescence is rare.

On the other hand, autism is an early onset condition (12-24 months of age) characterised by persistent deficits in social communication as well as restricted and repetitive behaviour patterns.

It is crucial to think that in autism, as in other conditions, things are not watertight and unique in their expression.