Adverse effects
These are principally anticholinergic:

Dry mouth
Blurred vision
Cognitive changes
Drowsiness
Constipation
Urinary retention
Tachycardia
Anorexia
Severe delirium and hallucinations (in overdose)While some studies suggest that use of anticholinergics increases the risk of tardive dyskinesia (a long-term side effect of antipsychotics), other studies have found no association between anticholinergic exposure and risk of developing tardive dyskinesia, although symptoms may be worsened.Drugs that decrease cholinergic transmission may impair storage of new information into long-term memory. Anticholinergic agents can also impair time perception. Pharmacology
Benzatropine is a centrally acting anticholinergic/antihistamine agent. It is a selective M1 muscarinic acetylcholine receptor antagonist. Benzatropine partially blocks cholinergic activity in the basal ganglia and has also been shown to increase the availability of dopamine by blocking its reuptake and storage in central sites, and as a result, increasing dopaminergic activity. Animal studies have indicated that anticholinergic activity of benzatropine is approximately one-half that of atropine, while its antihistamine activity approaches that of mepyramine. Its anticholinergic effects have been established as therapeutically significant in the management of Parkinsonism. Benzatropine antagonizes the effect of acetylcholine, decreasing the imbalance between the neurotransmitters acetylcholine and dopamine, which may improve the symptoms of early Parkinsons disease.Benzatropine analogues are atypical dopamine reuptake inhibitors, which might make them useful for people with akathisia secondary to antipsychotic therapy.Benzatropine also acts as a functional inhibitor of acid sphingomyelinase (FIASMA).Benzatropine has been also identified, by a high throughput screening approach, as a potent differentiating agent for oligodendrocytes, possibly working through M1 and M3 muscarinic receptors. In preclinical models for multiple sclerosis, benzatropine decreased clinical symptoms and enhanced re-myelination.
In 2014, Gambetti P., Zou W.Q., and coworkers found that approximately 54% of mice inoculated with VPSPr brain homogenates exhibited histopathologic lesions and 34% harbored abnormal PrP similar to that of VPSPr on the first passage but no prion disease was detected on the second passage,[10] suggesting that the infectivity of the pathological PrP from VPSPr is lower compared to that from the most common sporadic CJD. See also
Creutzfeldt–Jakob disease

References
8. Xiao X, Yuan J, Haïk S, Cali I, Zhan YA, Moudjou M, Li B, Laplanche JL, Laude H, Langeveld J, Gambetti P, Kitamoto T, Kong Q, Brandel JP, Cobb BA, Petersen RB & Zou WQ. Glycoform-selective prion formation in sporadic and familial forms of prion disease. PLoS ONE, 2013; 8:e58786. 9. Zou, WQ, Gambetti P, Xiao X, Yuan J, Langeveld J & Pirisinu L. Prions in variably protease-sensitive prionopathy: An update. Pathogens 2013; 2(3): 457-471. 10. Notari S, Xiao X, Espinosa JC, Cohen Y, Qing L, Aguilar-Calvo P, Kofskey D, Cali I, Cracco L, Kong Q, Torres JM, Zou W & Gambetti P. Transmission characteristics of variably protease-sensitive prionopathy. Emerg Infect Dis 2014, 20:2006-14. External links

Caroline Parkinson (13 August 2010). "Brain disease could affect more people, research finds". BBC News.