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Blues go untreated in Parkinson's patients ~~ Depression in PD often confused with other symptoms, worsens impact of motor function problems

By Samuel Jarjour
JULY 30, 2007 ~ VOLUME 4 NO. 13
http://www.nationalreviewofmedicine....tice07_13.html

Depression in Parkinson's disease (PD) is common, often untreated and exacerbates motor function problems, suggests a study published online in Neurology June 20. It appears depression may simply go unnoticed or get mistaken for other PD symptoms, the researchers found. The study suggests better depression treatment would improve PD patients' overall daily functioning.

UNDER THE RADAR
The multi-centre study included 413 subjects with early, untreated PD. "Despite the early course of the PD, clinically significant depression was still common," says study author Dr Richard Camicioli, a neurologist at the University of Alberta. "Almost 30% of patients had symptoms."

Disturbingly, of those, fully 40% weren't being treated or sent for psychiatric referrals. There are several possible explanations for this undertreatment. "Some doctors attribute depressive symptoms, like fatigue or sleep disturbances, to the Parkinson's itself," says Dr Camicioli. "This raises the possibility that treatment ought to be done differently with these patients."

Dr Camicioli and his team also looked at whether depression was associated with motor function, the need for symptomatic PD therapies and level of daily life functioning. They found that depression was loosely tied to worsened motor skills, but significantly linked with patients' chances of being prescribed PD drugs. It also played a role in impaired daily living activities like eating, dressing and bathing.

PD blues: a chemical connection?

The causal nature of the link between depression and PD is poorly understood. One explanation is that depression is a relatively normal response to living with a debilitating progressive disease.

But there may be a more fundamental connection. "Neurochemical and structural changes in Parkinson's could go well beyond the dopaminergic system," says Dr Camicioli. Some experts even wonder whether the PD etiology in depressed patients may actually differ from that in non-depressed PD patients. While he cautions it's speculative to say so, Dr Camicioli considers it an interesting possibility. "This research may reveal surprising things. It could shed light on our understanding of Parkinson's, and depression too. It's an interesting area to be working in right now."

QUALITY TREATMENT
In cases where depression was recognized, doctors were often more comfortable treating their patients with PD drugs than with antidepressants, hoping that mood improvements will ride the coattails of motor improvements. But the PD drugs don't always resolve the depression. "We're not sure that that's the only thing we could do to improve these patients' quality of life," says Dr Camicioli.

There's also the possibility that some antidepressant treatments may worsen PD symptoms. Little data is available on the effects of antidepressants specifically in PD patients, so doctors are often reluctant to prescribe them. "We have much better guidelines on treating the motor symptoms," says Dr Camicioli.

So what's a doc to do? "Doctors ought to screen for depression in people with Parkinson's. The Geriatric Depression Scale is fairly easy to use," says Dr Camicioli. "If patients are depressed in our clinic we assess suicide risk, and initiate antidepressant treatment. We'll also give a psychiatric referral, or get patients in touch with support groups or counsellors." He suggests doctors carefully monitor patients for antidepressant side effects.

Dr Camicioli hopes his research can raise awareness of depression in Parkinson's disease. "Depression is something for family and friends of Parkinson's patients to really keep an eye open for."

The study hints at new research horizons. "Being a secondary analysis of trials data, the study didn't exactly fill a gap, but we definitely found one." Although he considers the problems caused by PD's non-motor aspects pressing, Dr Camicioli suspects interest in cognitive impairments, depression and sleep issues in PD is growing. "We're realizing how important this is from a general quality of life perspective," says Dr Camicioli.