Treatment issues related to sleep and depression.

In the management of depression, the role of sleep and sleep disturbances is important for several reasons. The same neurotransmitter systems that regulate mood, interest, energy, and other functions that may be disturbed in depression also regulate sleep. Sleep disturbances may be responsive to treatment with some antidepressants and may be worsened during treatment with other antidepressants. Serotonergic neurons play a critical role in modulating the onset and maintenance of sleep, and it is thought that insomnia in depression is caused by dysfunction of serotonergic systems. For a significant minority, SSRIs can have negative effects on sleep patterns resulting in insomnia that requires concomitant sedatives or anxiolytics. By contrast, agents that block the serotonin type 2 (5-HT2) receptor have beneficial effects on depressive insomnia. For example, a recent 8-week study comparing the effects of nefazodone and fluoxetine on sleep disturbances in outpatients with nonpsychotic depression and insomnia found that fluoxetine was associated with approximately a 30% increase in the number of nocturnal awakenings whereas nefazodone was associated with about a 15% decrease, a net difference of 45%. Long-term studies must be conducted to determine whether sleep benefits provided by the newer antidepressants will continue past the acute treatment phase.