Management of catatonia in Parkinson’s disease with comorbid bipolar disorder: A case report and review of literature

Table 2 Differentiating drug-induced and idiopathic Parkinson’s disease

Clinical features and other characteristics	DIP	IPD
Cause	Blockade of dopamine D2 receptors. Temporal association with offending medications	Degeneration of nigrostriatal dopaminergic neurons
Sex distribution	More common in women	Slightly more common in men
Symmetry	Usually bilateral and symmetric features, but asymmetric features may be present in up to half of the patients	Unilateral and/or asymmetric features
Bradykinesia	More prominent	Present
Rigidity	More prominent	Present
Resting tremors	Relatively absent	Present
Coexistence of tardive dyskinesia	More common	Less common
Freezing gait	Relatively absent	Present
Olfactory dysfunction	Absent	Present in about 90% of the patients at any stage of IPD
Other non-motor symptoms	Absent	Sleep disturbance and urinary dysfunction may be present
Response to levodopa	Lack of response or a diminished response	Usually, a good response that is diagnostically useful
Dopamine transporter imaging by SPECT or PET	Medications causing parkinsonism, including antipsychotics, have negligible affinity for the transporter, so scans may demonstrate normal uptake even with significant DIP	Transporter uptake in the striatum is significantly decreased in patients with IPD, even in early stages of the disease
Resolution of symptoms	DIP usually resolves within months of stopping the offending drug, but unmasked PD may persist or progress in 10%-50% patients	Symptoms increase with time

PD: Parkinson’s disease; DIP: Drug-induced parkinsonism; IPD: Idiopathic Parkinson’s disease; SPECT: Single-photon emission computed tomography; PET: Positron emission tomography.