There is some overlap in symptoms between autism spectrum disorder (ASD) and borderline personality disorder (BPD), such as difficulties with emotional regulation, problems maintaining social relationships, and low self-esteem, among others. For this reason, some people are often diagnosed with BPD when they actually have autism. This is especially common in women.

However, when we talk about ASD, we're talking about the person's neurodevelopment, so we need to be able to see this expression of autism from the earliest years of life. In contrast, in a personality disorder like BPD, the traits can be seen in adolescence, but it shouldn't be diagnosed until adulthood. On the other hand, autism has differentiating features such as intense or restricted interest in a particular subject, or differentiated sensory processing, which are not present in BPD. These two characteristics, along with the developmental stage and the observation of other symptoms, should help in making a correct diagnosis.

In any case, any person, autistic or not, in a complex family environment, can develop dysfunctional behavioral patterns or personality traits. Current diagnostic manuals do allow for the joint classification of ASD and BPD, although some expert professionals consider this inappropriate. This is an area that will require further research in the coming years.