Diagnostic overshadowing (DO) is identified as a contributor to the missed diagnosis of individuals with an autism spectrum disorder (ASD). It has been used predominantly in the scientific literature and clinical settings to describe a phenomenon where a person's symptoms and behaviors are attributed solely to their primary diagnosis, rather than being recognized due to co-occurring conditions. DO is seen across many developmental disorders; however, females with autism may have a more difficult time getting diagnosed than males with autism because traditional diagnostic criteria for autism are often based on research that has primarily focused on males with autism. Likewise, the efficacy of approved psychopharmacological like selective serotonin reuptake inhibitors (SSRIs) and cognitive behavioral therapy (CBT) in individuals with ASD is not well established. Amidst these challenges, it’s imperative to underscore the need for screening these disorders and provide informed evidence-based treatment alternatives for shared decision-making. Mirtazapine has low but promising findings, though modified CBT has superior empirical support in the treatment of co-occurring conditions associated with ASD.