SAN FRANCISCO – Prodromal anxiety and depression are common in Parkinson’s disease and may develop years earlier than conventionally thought, according to data presented at the 2016 congress of the International Psychogeriatric Association.

“In some cases, the psychiatric prodrome can appear 25 or more years earlier than the onset of motor symptoms,” said Andrea Seritan, MD, a geriatric psychiatrist at the University of California, San Francisco. Psychiatrists need to keep this fact in mind when treating patients with anxiety or depression, and refer them to a neurologist if they notice or are informed of motor symptoms, she emphasized.

Dr. Andrea Seritan Amy Karon/Frontline Medical News

Dr. Andrea Seritan

Patients with Parkinson’s disease often have developed anxiety or depression before the onset of motor symptoms. Historically, this psychiatric prodrome was thought to begin anywhere from 5 to 10 years before motor symptoms, “depending on which expert you ask,” Dr. Seritan said. But after observing that some of her Parkinson’s patients reported decades-long histories of anxiety or depression, she and her colleagues reviewed medical charts for 39 patients aged 50 years or more with confirmed Parkinson’s disease who were referred for psychiatric evaluation at the UCSF Movement Disorder and Neuromodulation Center in 2015 or 2016. A total of 28 patients (72%) were men, mean age at referral was 65 years (standard deviation, 7.6 years), and the patients had been diagnosed with Parkinson’s disease an average of 12 years previously (standard deviation, 6.7 years).

At referral, a total of 34 (87%) patients met DSM-5 criteria for major depressive disorder, dysthymia, or an unspecified depressive disorder, while 68% met DSM-5 criteria for generalized anxiety disorder, panic disorder, social anxiety disorder, other anxiety disorders, Dr. Seritan said. About two-thirds of patients had comorbid depression and anxiety. Other DSM-5 diagnoses included impulse control disorders (15% of patients), substance abuse disorders (13%), and mild (21%) or major (13%) neurocognitive disorders.

Exactly 50% of patients had depression preceding their Parkinson’s disease diagnosis, while 43% of patients had prodromal anxiety, Dr. Seritan and her colleagues determined. The average age of onset of psychiatric symptoms was in the 30s, but this ranged from childhood or adolescence into the 60s. Mean ages of Parkinson’s diagnosis were much later – 58 years for patients whose primary prodrome was anxiety and 56 years for patients whose primary prodrome was depression, with a standard deviation of 9.8 years for each group.

The findings suggest that a decades-long prodrome of anxiety or depression is common in Parkinson’s disease, Dr. Seritan concluded. Psychiatrists should be alert to the possibility of Parkinson’s disease in patients with depression or anxiety, because individuals with movement disorders can be very susceptible to the side effects of antidepressants and antipsychotics, she emphasized.

Dr. Seritan reported no funding sources and had no conflicts of interest.