Objective: This article aims at exploring distinctive hallmarks of autistic disorders compared to other groups presenting mimicking and/or overlapping conditions. Method: The exploratory study involved 196 children with autism, intellectual disability, language impairment and psycho-affective disorders previously referred to an autism diagnostic service. The autism discriminative tool (ADT), a behavioural checklist, was used to compile and analyse the children's profiles based on the clinical information gathered during diagnostic assessments. All samples were compared and analysed separately according to the checklist's four domains. Results: Children with autism showed greater frequency and severity of impairments on the ADT's social and communication categories. These children also differed from other groups in terms of specific rigid behaviours and high frequency of atypical sensory responses. Conclusions: Results illustrate the psychopathology of autism spectrum disorder suspected children referred to a specialized autism diagnostic service, doing so by providing us with specific clinical profiles.