Studies have shown that the newer classes of antidepressants, such as selective serotonin reuptake inhibitors (SSRIs), are equally or more effective than older drug classes. The side effects of such drugs, such as their effect on sleep, have not been fully established and comparisons between such drugs have been scarce.

Dr Jane Hicks and colleagues from the University of Bristol investigated the effects on sleep of two newer antidepressants – paroxetine and nefazodone, a serotonin receptor antagonist – in order to determine whether differences between them relate to the efficacy of the drugs.

The researchers identified 40 individuals with moderate to severe depression – according to DSM-IV and the Hamilton Rating Scale for Depression – as well as reported sleep disturbance to take part in the study.

The patients received either paroxetine (20-40mg/day) or nefazodone (400-600mg/day) for a period of eight weeks, and were assessed regularly, both objectively and subjectively, for the effects of the drugs on both sleep and depression levels over the study period.

The researchers found that sleep efficiency and total sleep time increased with nefazodone early on in the study period, with patients reporting improved sleep on days 3 and 10. However, few differences existed between the treatment groups by the end of eight weeks, with only stage 1 sleep and number of awakenings higher in the paroxetine group.

Increased sleep disturbance was reported early on in the paroxetine group and rapid eye movement sleep was reduced in these patients.

The authors suggest that negative early effects of antidepressants on sleep may be important, as patients may be more likely to stop taking or be unhappy with their medication.

Reference: Hicks et al, British Journal of Psychiatry 2002;180:528-535
© Health Media Ltd 2002
http://www.health-news.co.uk