Differences in reciprocal social interaction and communication, intense focal interests, repetitive movements and sensory sensitivities. There are no traits or sensitivities that are unique to autistic people, but the combination of features and the degree to which they occur is what characterises the condition. There is ongoing debate about whether autism is a disorder, a condition or a naturally occurring difference. The lifetime experiences of autistic adults through into older life are still largely unknown. It is important to treat co-occurring conditions in autistic people with the evidence-based treatments used for non-autistic people until and unless clear evidence emerges showing a different approach is preferable. Autism is not a mental illness or learning disability. Rather, it is a difference where traits and sensitivities can have positive and negative impacts on a person’s life, and these impacts can change at different times or in different circumstances. It is vital to recognize and understand autism in order to make reasonable adjustments to the assessment and treatment plans when treating co-occurring disorder in an autistic person.