Antidepressant exacerbation of spasticity

Patients with spinal cord injury (SCI) may develop depression. This may be related to adjustment to living with an SCI in addition to dealing with complications of the injury, such as spasticity. Pharmacologic treatment of depression can be difficult because of neurochemical and receptor changes that are associated with SCI. Newer antidepressant agents are purported to have selective activity by alteration of serotonergic neurotransmission. A case report is presented that illustrates exacerbation of spasticity by this family of antidepressant medications. Mechanisms possibly explaining this exacerbation of spasticity are the effects of serotonin on motor neuron and reflex activity, denervation supersensitivity, and the serotonin syndrome. Understanding the relationship between serotonergic systems and spasticity can be important in treating depression in patients with spasticity.