Neurodevelopmental Disorders (NDD) begin in childhood and affect cognitive, behavioral, and socioemotional functioning. Difficulties in the initial identification of symptoms by caregivers, as well as the great variability in the cognitive profiles observed in these children, are some of the main challenges faced by psychologists and psychiatrists when making an accurate diagnosis. To contribute to this understanding, this dissertation investigated, in two complementary studies, factors involved in the search for psychiatric care and the cognitive heterogeneity of these disorders. The first study analyzed the profile of initial subjective complaints (ISC) reported by caregivers of children and adolescents treated at a psychiatric outpatient clinic, exploring their relationship with the diagnoses of NDD and anxiety disorders. Learning difficulties were the most frequent complaints (42.6 percent), followed by hyperactivity/impulsivity (41 percent) and defiant/oppositional behaviors (39.3 percent). Restricted/repetitive patterns and inflexibility distinguished individuals with Autism Spectrum Disorder (ASD) from those with Attention Deficit/Hyperactivity Disorder (ADHD) or Intellectual Development Disorder (IDD). The second study explored intellectual heterogeneity in children and adolescents with ADHD, ASD, and/or IDD, through neuropsychological tests. A hierarchical cluster analysis revealed three distinct profiles: Preserved Cognitive Performance (PCP), Below Average (MI), and Global Impairment (GR), differing by the degree of cognitive impairment. ANOVAs indicated significant differences in IQ scores and in the cognitive measures analyzed (p less than or equal to .001) among the three groups. While patients with ASD and/or ADHD were distributed between PCP and MI, the GR group was composed mainly of children with IDD. These findings reinforce the need for interventions targeting externalizing symptoms, which tend to be more noticeable by caregivers, and psychoeducation on internalizing symptoms, which may go unnoticed. Furthermore, the identification of neuropsychological profiles that are distinguished based on the degree of impairment highlights the cognitive heterogeneity in NDD, helping in the planning of more appropriate therapeutic strategies according to cognitive functioning.