A third of educational psychologists do not know how many looked- after children attend the schools where they work. And one in 10 says they do not know whether the children they work with individually are in care.
Researchers working for the Association of Educational Psychologists surveyed 107 in the field across five local authorities.
While two-thirds acknowledged that they were expected to give priority to pupils in care, many said these children were not identified to them.
Others felt they had insufficient specialist knowledge to help these children. One said: "I think they need to know about the psychological impact of loss, bereavement, separation and post-traumatic systems from abuse or neglect, and how that affects children."
There are approximately 60,000 looked-after children at any one time, but many more pass through the system during the year. As a group, these pupils consistently underachieve. Last year, only 13 per cent of pupils in care achieved the GCSE benchmark, compared with 62 per cent of all children.
But only a third of educational psychologists had been asked to provide training to school staff about issues that may arise with children in care. And almost as many had never worked with other professionals to support them.
Almost half the respondents said their schools did not have a designated teacher for looked-after pupils. Where these teachers did exist, they rarely worked with educational psychologists, and one in 10 never sought psychologists' advice.
When joint working did take place, it was not always helpful. Some interviewees complained that psychological terms were being bandied around by school staff who had little idea about what they meant. For example, the term "attachment issues" was regularly used to describe looked-after children, without teachers understanding what exactly these involve.
One interviewee said: "Often, schools do disastrous things. So, for example, a girl that has changed placements a lot . the school changed her geography group. She came in on a Monday morning and suddenly had a new group to go to . To me, that was evidence the school had no idea about how important stability was at that point."
Another said: "It's very difficult to comprehend some of the traumas that children have been through, without having had direct experience or direct knowledge."
Others talked about widespread misconception of their roles and the subsequent duplication of work. This could be confusing for pupils.
But many educational psychologists felt that they, too, required more specialised training in order to be able to help looked-after pupils effectively.
"The greatest skill, I think, is sympathy for that feeling of being lost," one respondent said. "I mean, it must just be terrifying."