Antipsychotics May Boost Risk of Movement Disorders

Cross-sectional data suggest link in patients with depression and schizophrenia

June 23, 2016 By Kristina Fiore

BERLIN -- Antipsychotics are tied to a higher risk of movement disorders in both depressed and schizophrenic patients, researchers reported here.

In a cross-sectional study, being on typical antipsychotics carried an increased risk of movement disorders in both schizophrenic (OR 3.4, 95% CI 1.2 to 9.8) and depressive patients (OR 6.1, 95% CI 2.4 to 15.3), according to Santiago Perez-Lloret, MD, of the National Research Council in Buenos Aires, and colleagues.

However, the risk was not increased among those on atypical antipsychotics, they reported at the International Congress of Parkinson's Disease and Movement Disorders here.

"We don't know why the risk was higher for depressed patients compared with schizophrenic ones, but this is important because clinical trials are not good for assessing the safety of drugs, and this is one of the first postmarketing studies," Perez-Lloret told MedPage Today.

"It's important for physicians to be aware of the possibility of these disorders and to have a close look when they give antipsychotics to their patients," he added.

Ron Postuma, MD, of McGill University in Montreal, who was not involved in the study, told MedPage Today that the findings suggest that it "really does seem to be the medications themselves driving the effect on movement disorders, rather than the underlying condition."

Some studies have shown that antipsychotics are related to movement disorders in schizophrenia patients, but it is hard to tease out cause and effect, the researchers explained. The drugs have also been prescribed to patients with depression, and it is not clear if the drugs are related to movement disorders in this population as well.

Perez-Lloret and colleagues therefore looked retrospectively at 814 patients with depressive disorders or schizophrenia treated at several clinics in Central America. Overall, 25% of the patients had schizophrenia, 33% had major depression, and 42% had bipolar depression.

Overall, 7.5% of patients had movement disorders, which included 10.8% of those with schizophrenia and 6.4% of those with depression.

The most common movement disorder was tremor, at 5.9% of schizophrenia patients and 3.6% of depressive patients, followed by akathisia (3.4% and 1.5%, respectively) and tics (2.9% and 3.6%).

Factors associated with movement disorders included being male (OR 2.21, 95% CI 1.26 to 3.88), being on typical antipsychotics (OR 4.49, 95% CI 1.19 to 16.89), and being on lithium (OR 4.55, 95% CI 1.18 to 17.54).

Atypical antipsychotics and antidepressants were not associated with movement disorders, the researchers noted.

Being on typical antipsychotics was associated with an increased risk of movement disorders for both schizophrenia patients (OR 3.4, 95% CI 1.2 to 9.8) and depressive patients (OR 6.1, 95% CI 2.4 to 15.3).

That risk was significantly higher for depressive patients (OR 4.5, 95% CI 1.6 to 12.3), but Perez-Lloret said the reasons for this association are not clear.

He added that both groups also reported worse quality of life if they had a movement disorder.

When asked about potential mechanisms for the association, Perez-Lloret said that the researchers "really don't know: These patients have an alteration in dopaminergic pathways, which may by itself lead to movement disorders, so there may be an interaction at that level."

He acknowledged that the cross-sectional nature of the study makes it impossible to draw conclusions about those relationships, and noted that other confounders could be at work, including the fact that some patients who experience movement disorders may be switched to other drugs -- which could account for the lack of an association between atypical antipsychotics and movement disorders, he said.

"So we can't exclude the possibility that being on atypical antipsychotics is also a risk factor for movement disorders."

http://www.medpagetoday.com/MeetingCoverage/MDS/58719?xid=nl_mpt_DHE_2016-06-24&eun=g972365d0r