Dear Editor,

the term “spectrum” is commonly used to characterize mental health illness including a variety of symptoms and behavioral patterns linked to a recognized construct [1]. In 2013, the Diagnostic and Statistical Manual of Mental Disorders 5th edition (DSM-5) [2] introduced the diagnosis of Autism Spectrum Disorder (ASD) with different levels of impairment, eliminating the diagnosis of Asperger's Disorder, incorporating it into the High-Functioning level of the ASD (HFA). HFA is a term applied to people with autism who are deemed to be cognitively higher functioning than other people with autism. They generally present normal language or general intellectual abilities, yet in everyday life, they avoid eye contact and do not spontaneously interact with people, show specific impairments in understanding the intentions of others and lack fast intuitive judgments about social contexts [3,4].

A systematic review has reported that the outcome in the adult life of ASD subjects is modest at best, in terms of psychosocial functioning, adaptive behavior or quality of life [5]. Quality of life, independent living and marital status have been reported to be significantly worse in HFA than in neurotypical control individuals [6,7].

Recently, clinical interest in mild forms of HFA has increased, especially for subclinical manifestations of the autism spectrum. Past literature has highlighted how subthreshold autistic traits can represent risk factors for the emergence of psychiatric disorders and worsen the trajectory of other comorbid disorders [8,9]. Indeed, people with subthreshold autistic traits often come to clinical attention when comorbid mental disorders arise [10].

Some studies have highlighted a certain degree of similarities between ASD and Borderline Personality Disorder (BPD) [11] involving social functioning, miscommunications, incorrectly assumed intentions, emotional outbursts but also difficulties in Theory of Mind tasks and in understanding emotions [12]. Moreover, autistic traits have been found in BPD patients who reported a history of abuse [13].

Scientific literature has shown that patients with ASD perceive higher stress and report poorer ability to cope effectively with stress in everyday life than controls [14]. Moreover, a higher level of perceived stress has been associated with lower levels of quality of life [15]. Numerous conditions, both internal (psychiatric comorbidities, medical condition, inflexibility, etc.) and external (routine changes, family conflicts, relational dynamics, etc.) can lead to increased stress in very vulnerable people such as people with ASD and vice-versa [16,17]. Furthermore, patients with ASD are often exposed to traumatic experiences and are at increased risk of developing Post-Traumatic Stress Disorder [18].

Several studies have been focused on the overlap between the clinical characteristics of ASD and Anorexia Nervosa [19,20]. Clinical symptoms of eating disorders in terms of obsession for proper nutrition, focus on weight loss, concern and rituals about food and food consumption, and rumination about eating may be common to both ASD and Obsessive-Compulsive Disorder [21].

Recently, symptomatic overlap between ASD and Social Anxiety Disorder has been reported [22].

Furthermore, the scientific literature is witnessing a growing research interest regarding the overlapping symptomatology between autistic traits and psychosis [23-25].

Since autistic traits may impact the clinical presentation of other mental disorders and may be a risk factor for other disorders or towards suicidality [26-28], some researchers developed psychometric scales to identify autistic symptoms from a dimensional perspective [29-32]. However, these scales cannot be used to make diagnoses.

In our opinion, clinicians still pay little attention to investigating autistic traits in the clinical psychopathology of patients suffering from mental disorders, often determined by little training regarding ASD and even more so on subthreshold symptoms. The authors want to speculate on the hypothesis of considering autistic traits as the basis of trans-nosographic psychic functioning common to numerous mental conditions. Moreover, this hypothesis should lead to increasingly personalized therapeutic interventions.