714 Medication-Induced Movement Disorders
Anxiety and depressive disorders. Discontinuation symptoms often resemble symptoms
of a persistent anxiety disorder  or a return of somatic symptoms of depression for which
the medication was initially given.
Substance use disorders. Antidepressant discontinuatio n syndrome differs from sub-
stance withdrawal in that antidepressants th emselves have no reinforcing or euphoric ef-
fects. The medication dosage has usually not been increased without the clinician’s
permission, and the individual generally does no t engage in drug-seeking behavior to ob-
tain additional medication. Criteria for a substance use disorder are not met.
Tolerance to medications. Tolerance and discontinuation symptoms can occur as a
normal physiological response to stopping medication after a substantial duration of
exposure. Most cases of medication tolerance can be managed through carefully con-
trolled tapering.
Comorbidity
Typically, the individual was initially started on the medication for a major depressive dis-
order; the original symptoms may return  during the discontinuation syndrome.
Other Adverse Effect of Medication
995.20 ( T50.905A )Initial encounter
995.20 ( T50.905D )Subsequent encounter 
995.20 ( T50.905S )Sequelae
This category is available for optional use by clinicians to code side effects of medication
(other than movement symptoms) when these ad verse effects become a main focus of clin-
ical attention. Examples include severe hypotension, cardia c arrhythmias, and priapism.