Sleep disorders from SSRIs

Now Schenck, Mahowald, and others tell us that not only does SSRI treatment potentiate eye movements in NREM sleep, but that it may also potentiate dream enactment in REM sleep. In other words, SSRIs may induce the REM sleep behavior disorder How does this work In addition to releasing the saccade generator from inhibition, the drug appears to interfere with the spinal cord inhibitory mechanism that normally blocks the central motor commands that so convincingly animate our dreams but do not result in real behavior. 

RBD is characterized by a relative absence of the atonia characteristic of REM sleep. This lack of atonia permits the physical acting out of dream mentation, particularly dreams involving confrontation, aggression and violence. RBD is seen most frequently in older men. RBD occurs in both acute and chronic forms. Acute RBD can occur during withdrawal from alcohol or sedative-hypnotics. RBD has also been induced by the tricyclics, SSRIs and venlafaxine. The chronic form of RBD may occur as part of an identifiable underlying neurological disorder, but typically is idiopathic. RBD may also be an initial manifestation of parkinsonism. RBD is very responsive to clonazepam, although this use has not been FDA approved. 

Serotonin, also known as 5-hydroxytryptamine (5-HT) is biosynthesized from tryptophan and is a neurotransmitter. Serotonin plays an important role in many behaviors including sleep, appetite, memory, and mood [52]. People with depressive disorders exhibit low levels of serotonin in the synapses. Protonated serotonin binds to a serotonin reuptake transporter protein, sometimes referred to as the serotonin transporter (SERT) and is then moved to an inward position on the neuron and subsequently released into the cjdoplasm. Selective serotonin reuptake inhibitors (SSRI) bind with high affinity to the serotonin binding site of the transporter. This leads to antidepressant effects by increasing extracellular serotonin levels which in turn enhances serotonin neurotransmission [53]. The SSRI class of antidepressants has fewer side effects than the monoamine oxidase inhibitors. 

---