Age and onset age may influence bipolar treatment response

By Eleanor McDermid, Senior medwireNews Reporter

Some differences in treatment response emerge when patients with bipolar disorder are grouped according to their age and their age at bipolar onset, say researchers.

The team studied patients from the European Mania in Bipolar Longitudinal Evaluation of Medication (EMBLEM) study. Of the patients, 1191 were younger than 50 years, and 240 were older than 60 years. In the older group, 134 patients had been diagnosed with bipolar disorder before the age of 50 years (early onset), whereas 63 were aged 50 years or older at diagnosis (late onset).

Baseline characteristics were broadly similar between the groups, except where influenced by factors such as disease duration, and for the most part recovery, remission, recurrence and relapse did not differ.

However, having achieved remission, older patients were significantly more likely than younger patients to recur, at 40% versus 23%. They recurred in a significantly shorter time, irrespective of whether they had early- or late-onset bipolar disorder.

“These results suggest that in the older patients, remission and recovery are as easy to achieve but more difficult to maintain compared with that in younger patients”, say lead researcher Frits Oostervink (GGZ Haagstreek Rivierduinen, Leidschendam, the Netherlands) and co-workers.

Reasons for this may include a progressive disease course, medical comorbidities and nonadherence to medication, they say. They also note that antidepressants were more frequently used in older than younger patients, which may be associated with, or even cause, a higher cycle frequency.

Within the older group, patients with late-onset bipolar disorder were nonsignificantly more likely to recover than those with a longer duration of disease, at 32% versus 21%. Their average time to recovery was also shorter, although again not significantly so, at 490 versus 546 days.

When compared with the younger group, older patients with early onset were significantly less likely to recover, at 21% versus 33%, and significantly more likely to relapse, at 42% versus 34%.

Besides the greater use of antidepressants, older patients were less likely than younger patients to be taking atypical antipsychotics and more likely to be receiving concomitant psychiatric medications. There was also a trend towards less use of lithium in older patients (18.7 vs 25.4%).

“Combined medication treatment was the rule rather than the exception in all four groups”, notes the team in the International Journal of Geriatric Psychiatry. “This is consistent with evidence-based treatment guidelines and may reflect the complexity of managing bipolar disorder.”

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