Rick and imark
How strangely coincidental that I just wrote to another researcher today about this very topic. Only his qurestion was why do animal models which are highly successful in pretrials often go so badly in Phases I and II and are stopped? You have hit upon it right here.

Animals have similar body functions, and even some haave emotions (grief, fear, etc.), but non-human animals don't reason or have psychosis, depression and other emotional factors, especially animals lesioned with poisons like MTPT. Traumatic pasts are literally the catalysts that cause several neurological illnesses. The psychiatrists and geriactric pstchologists know t his, but it's never tested in trials too find if a therapy improves movement. Bu t they are inseparable, in my opinion (and several others).

Read this: "The researchers examined Department of Veterans Affairs patient records from fiscal year 2008, comparing the rates of antipsychotic drug prescriptions among two groups: 2,597 patients with Parkinson's disease and psychosis with and without dementia and 6,907 patients with dementia and psychosis but without Parkinson's disease; 97.3% of the patients studied were men.

"More men are diagnosed with Parkinson's, and men are more likely to develop dementia," says Weintraub.

An estimated 60% of Parkinson's patients will experience some form of psychosis during their illness, according to the study. Weintraub and colleagues found that half of all patients with Parkinson's and psychosis were treated with antipsychotic medications.
. . .
"This study is very important because it highlights the problem that clinicians face," says Fernandez. "The problem is it's not very easy to treat, and few patients will be completely treated"
-Source: http://www.webmd.com/parkinsons-dise...spite-warnings -

We have a lot of convincing to do to have a trial designed to include such important variables into its outcome measures. And it seemingly would be simple enough. You could do something as obvious as provide psychological counseling to one group, and not to the control to see if intervention makes a difference not just in behaviors, but in mootor slills development.
Peg
Peggy