Repetitive behaviours in behavioural variant frontotemporal dementia (bvFTD) are more accurately described as ‘impulsive’ than ‘compulsive’, signalling a need for a different pharmacological approach, a conference has been told.
Speaking at the 11th International Conference on Frontotemporal Dementias in Sydney, Dr Mario Mendez a behavioural neurologist from the University of California, Los Angeles (UCLA) said he had long suspected the repetitive behaviours that define bvFTD are not compulsive in origin.
A comparison of repetitive behaviours in bvFTD and obsessive compulsive disorder (OCD) provided early evidence to support the idea, he told the conference.
Repetitive behaviours in OCD appeared to be driven by a need to relieve anxiety whereas in bvFTD patients they stemmed from poor impulse control, resulting in reward-seeking behaviour such as verbal repetitions, motor stereotypies and unnecessary trips to the bathroom, said Dr Mendez, who directs the Focal-type Dementia Clinic and Program.
“They are not like OCD, they are more like loss of control driven by immediate stimulus with some kind of reward, and not due to obsessional thinking or anxiety or the need for relief.”
Dr Mendez said his research had identified key differences in the repetitive “compulsive-like” behaviours shown by 59 patients with clinically probable bvFTD, compared to descriptions of compulsive behaviours in OCD patients in the literature.
In OCD patients, the most common behaviours included cleaning, checking and counting and hoarding.
These behaviours were “negatively-driven”, meaning patients were motivated by the need to relieve anxiety or by obsessional thinking.
In contrast, in bvFTD patients the most common behaviours were verbal repetitions (palialia, echoalia), motor stereotypies, hoarding and tic-like movements.
This group did not report distress if they were prevented from completing an act, or relief after completing it.
“We’re showing in our work that they [repetitive behaviours] are not compulsions, they are impulsions,” Dr Mendez told the limbic.
These findings suggest a need to go beyond the SSRIs typically used to treat compulsive behaviours in bvFTD patients.
Anti-epileptic agents, lithium and beta blockers, could be trialled, with or without SSRIs, he suggested .
However this will likely require off-label prescribing, he added.