Child custody assessments under review after complaints about former psychologist's methods

A former Vancouver psychologist who has served as an expert witness in hundreds of court cases has agreed to review his assessments in a series of child custody cases in response to complaints about his methods.

Dr. Allan Posthuma signed an undertaking with the College of Psychologists of B.C. on New Year's Day, consenting to consult with a colleague in a review of his reports in five cases concerning parenting and custody disputes. He's also agreed to accept feedback on how to improve his practice.

The college's inquiry committee launched an investigation after receiving complaints about Posthuma's compliance with professional standards, according to a public notification.

"This includes allegations relating to the registrant's use of appropriate assessment methods and gathering sufficient information to support his professional opinions," the college's notice says.

"The concerns arose in the context of the committee's investigation of four complaints brought by members of the public, and a fifth matter investigated by the committee on its own motion,"

Posthuma has not admitted to breaching professional standards and the allegations against him have not been proven, the college says. When contacted by CBC, Posthuma said he was unable to comment on the undertaking.

As of Jan. 1, he is no longer registered as a psychologist in B.C.

A widely quoted expert

Posthuma is quoted as an expert in more than 200 legal rulings available online, mostly concerning family disputes and personal injury claims.

In the cases reviewed by CBC, the majority of B.C. judges who've heard his evidence over the years have described him as a knowledgeable witness and relied on his assessments to make their decisions.

But some have questioned his neutrality and expertise, and his assessments have occasionally been challenged by legal counsel and other psychologists offering testimony.

In one recent divorce and custody case, B.C. Supreme Court Justice Barbara Fisher described Posthuma's psychological assessment as "flawed." Posthuma had concluded a mother alienated her sons from their father, but the judge said that opinion "appears to be based largely on the absence of evidence."

However, Fisher also said she found other parts of Posthuma's report helpful in making her ruling.

In another family law case from 2016, Justice Bruce Butler said he could only accept into evidence a small part of Posthuma's psychological report, writing that on some questions the doctor had "ventured to offer an opinion which goes far beyond his limited foundation of fact and information."

Judges in earlier personal injury cases have described him at times as "argumentative and evasive" and occasionally acting as an "advocate" for one party or the other in court.

Posthuma had been registered as a psychologist in B.C. since 1977. This is the only public notification about his practice on file with the college.