Newer antidepressants effective and safe in Parkinson’s disease

NEWER antidepressants can improve mood in patients with Parkinson’s disease without worsening motor function, a new study has found.

The US trial suggested SSRIs and serotonin-noradrenaline re-uptake inhibitors did not have the adverse event profile of tricyclics including cardiac, autonomic and anticholinergic side-effects.

Earlier studies had found SSRIs can worsen Parkinsonian motor features and some were not well tolerated.

Researchers monitored 115 patients diagnosed with Parkinson’s disease and a major depressive disorder in the largest randomised controlled trial to date to evaluate commonly used antidepressants in such patients.

One third of the patients received paroxetine, one third received venlafaxine and the others were given placebo.

According to the Hamilton Rating Scale for Depression (HRSD), patients receiving paroxetine improved by 59%, venlafaxine  improved by 52% and the placebo group had 32% improvement. Three other depression scales gave similar results.

Adverse events were common in all three groups but most were not serious. Insomnia was reported less frequently among patients taking paroxetine compared to venlafaxine or placebo.

Importantly, none of the antidepressants worsened motor function or exhibited any significant side-effects, the authors said.

“I think this study is of great importance to both [clinicians] and patients because depression affects almost half of Parkinson’s patients,” neurologist Associate Professor Simon Lewis said.

Professor Lewis, a consultant at Royal Prince Alfred Hospital, Sydney, stressed that depression in patients with Parkinson’s disease arose from the disease process.

“Although most patients know about the loss of dopamine occurring in the brain, they are less aware that other chemical transmitters are also affected,” he said.

“Depression can actually predate the disease by several years.”

Treatment was “not just about making patients feel happy, it’s about responding to the chemical imbalances in their brain.”

Professor Lewis said that the antidepressants will be able to be taken alongside regular Parkinson’s medication.

Neurology 2012; online 11 April