Pupillary cholinergic sensitivity to pilocarpine increases in manic lithium responders.
BACKGROUND
The cholinergic hypothesis of affective disorders predicts that mania is a hypocholinergic state relative to monoaminergic activity. Treatments that increase cholinergic sensitivity are expected to improve manic symptoms.


METHODS
Ten male hypomanic or manic patients were treated with lithium carbonate (0.7-1.1 mEq/L) for 2 weeks. Cholinergic sensitivity was assessed prior to, and following treatments, using graded concentrations of pilocarpine eyedrops (.03-2.0%). Pupil size changes were quantified using an infrared pupillometer and ED50 values were referenced to maximal dilation with .5% tropicamide.


RESULTS
Lithium treatment decreased Bech mania ratings and ED50 values (p < .001). Improvements in mania with lithium treatment were closely correlated with decreases in ED50 (r = .88, p < .001).


CONCLUSIONS
These results support the cholinergic-adrenergic hypothesis and suggest that one possible mechanism for the antimanic effects of lithium may involve increasing cholinergic activity in relation to monoaminergic neurotransmission.
Sokolski
K N
KN
Mental Health Care Group, Veterans Affairs Medical Center, Long Beach, CA 90822, USA.
DeMet
E M
EM
D000287:Administration, Topical; D000328:Adult; D018692:Antimanic Agents / Q000627:therapeutic use*; D001714:Bipolar Disorder / Q000175:diagnosis / Q000188:drug therapy* / Q000523:psychology*; D018679:Cholinergic Agonists / Q000494:pharmacology*; D006801:Humans; D016651:Lithium Carbonate / Q000627:therapeutic use*; D008297:Male; D008875:Middle Aged; D009883:Ophthalmic Solutions; D010862:Pilocarpine / Q000494:pharmacology*; D011569:Psychiatric Status Rating Scales; D011680:Pupil / Q000187:drug effects* / Q000502:physiology*; D011941:Receptors, Adrenergic / Q000187:drug effects; D011950:Receptors, Cholinergic / Q000187:drug effects*; D012720:Severity of Illness Index
D018692:Antimanic Agents; D018679:Cholinergic Agonists; D009883:Ophthalmic Solutions; D011941:Receptors, Adrenergic; D011950:Receptors, Cholinergic; D010862:Pilocarpine; D016651:Lithium Carbonate