A complication is a medical condition that may be difficult. A comorbidity is presences of more than one medical complication.

The patient's high blood pressure and diabetes are examples of comorbidity, requiring careful management by healthcare providers.

Having more than one personality/anxiety disorder is very common. Having two or more disorders that share some sort of a relationship is called comorbidity. Whatever specific disorders you're asking about, I would do a quick google search on them searching for comorbidity. For example: comorbidity of anxiety disorder and bipolar disorder

He experiences a cognitive and developmental delay co-morbidity present is an anxiety disorder.

Heikki Lyytinen has written:

'Comorbidity and Developmental Neurocognitive Disorders'

'The Neuropsychology of Developmental Dyslexia'