Objectives: Patients with dementia (PWD) benefit from interdisciplinary care. Depression is a well-known risk factor for the progression of neurocognitive impairment and dementia; other psychiatric disorders (i.e. anxiety, post-traumatic stress disorder, bipolar disorder, psychotic disorders) also may confer an increased risk for dementia. PWD may also present with behaviours and psychological symptoms that overlap with psychiatric disorders. Our aim is threefold: (1) Review the current literature on managing psychiatric comorbidities in PWD. (2) Present an illustrative case series of PWD with psychiatric comorbidities. (3) Introduce a model of care on our Behavioural Neurology Unit (BNU) for treating PWD with psychiatric comorbidities.

Methods: Our BNU is a 20-bed quaternary inpatient unit for difficult-to-treat behaviours related to dementia. Psychiatric consultation is readily available to clinicians and often times for PWD with psychiatric comorbidities. We review best practices in managing these patients. We present a case series of PWD with psychiatric comorbidities predating their diagnosis of dementia who have significant behavioural and psychological symptoms and have failed other settings.

Results: Current guidelines for PWD do not discuss the management of psychiatric and neurologic comorbidities in detail. Among 26 cases, we highlight the judicious use of anticonvulsants, lithium, clozapine, and nabilone in PWD. We also demonstrate the importance of interdisciplinary care with primary care, neurology, psychiatry, and allied health support.

Conclusions: Dementia care is challenging and requires individualized attention and interdisciplinary collaboration. These challenges are augmented when dealing with psychiatric comorbidities. We advocate for increased attention and creative solutions to address these complex cases.