Comorbid autism spectrum disorder (ASD) is common and commonly missed in patients with PWS. Clinicians can diagnose autism through a brief questionnaire, without any laboratory testing. The latest diagnostic criteria for the diagnosis of ASD is described. Rather than viewing it as another diagnostic “label” for the patients, early recognition and management of comorbid ASD in PWS may have a significant long-term positive impact on the course of the illness. ASD-related language dysfunction can range from the patient being nonverbal all the way to near-normal cognitive and language functioning. Systemic advantages of being diagnosed with ASD are discussed, including entitlement to certain educational and healthcare services as delineated by state and federal governments. Securing these benefits is an important first step for patients. A case of a patient with PWS who also has autism is described to further elucidate the phenomenon of comorbidity. The advantages of therapies including applied behavioral analysis (ABA) as well as psychopharmacologic management are discussed.

Psychopharmacological interventions for the management of the neuro-behavioral manifestations of PWS that have been described throughout the book are the main focus of this particular chapter. A majority of patients with PWS are on one or more psychiatric medications by the time they reach adulthood. Patients with PWS are uniquely vulnerable to psychiatric illness and require a thorough assessment and diagnosis in order to receive appropriate treatment. This chapter outlines the main classes of medication that have been or, in our opinion, ought to be utilized in patients with PWS. We specifically address their common indications, side effects, and dosage recommendations, among other characteristics. Additionally, the complex phenomenon of drug–drug interactions is discussed in some detail, due to the high incidence of “polypharmacy” in PWS. We recognize that a significant portion of caregiver burden is attributable to neuro-behavioral symptoms and endeavor to provide the information necessary to guide providers in addressing that.

This chapter describes the underlying mechanisms and causes of anxiety in people with PWS. Underlying medical conditions such as hypothyroidism may cause anxiety. Response perseveration as a possible explanatory mechanism behind anxiety, obsessive-compulsive symptoms, and poor frustration tolerance is discussed. Co-occurring anxiety disorders are described through case examples. Anxiety can be a sign of an underlying disorder: panic disorder, GAD, etc. COVID-19 pandemic related worsening of anxiety is discussed.Patients with PWS of all ages are especially vulnerable to behavioral outbursts and psychological distress in the face of rapid and drastic changes to routine and lifestyle. Awareness of the wide variety of ways anxiety presents in PWS is needed for its early recognition and appropriate management.