There is strong evidence to support the theory that child abuse can cause schizophrenia, two researchers argued at medical conferences in London and Madrid this week.

Paul Hammersley, of the University of Manchester, and Dr. John Read, from the University of Auckland, New Zealand, reviewed 40 studies of psychiatric patients and found that most of these individuals were sexually or physically abused as children or adults. In a review of 13 studies of schizophrenics, they found abuse rates from a low of 51 percent to a high of 97 percent.

Citing the known link between the symptoms of post-traumatic stress disorder and schizophrenia, Hammersley and Read charge that many schizophrenic symptoms may actually be caused by trauma.

“I hope we soon see a more balanced and evidence-based approach to schizophrenia and people using mental health services being asked what has happened to them and being given help instead of stigmatizing labels and mood-altering drugs,” Read said in a statement.

“Child abuse was a reality for a large number of sufferers of psychosis,” Hammersley added. “The experience of hearing voices is consistently associated with childhood trauma regardless of diagnosis or genetic pedigree.”

Genes may still play a role in schizophrenia, but genes alone do not cause the illness, the researchers argue. Apart from Alzheimer’s disease, not a single gene has been shown to play a key role in any mental illness, they point out.

Schizophrenia is a disorder of altered emotions, thought processes, and perceptions of reality. In addition to hearing voices, schizophrenics may suffer hallucinations and delusions and have difficulty with memory and intellectual functioning. Symptoms of the disorder are most apt to appear in the late teens and 20s.

Hammersley and Read think all patients seen in the mental health arena should be asked about whether they have suffered any kind of abuse in their lifetime. They also think antipsychotic drugs should not be automatically doled out; rather these individuals should be offered psychological therapies more often.

“What is important about all this,” Hammersley told Reuters Health, “is whether or not mental health services change. Users of those services tell me over and over again, they are fed up being offered nothing but medication.”

The findings were scheduled for presentation at the Institute of Psychiatry in London and the 15th ISPS Symposium for the Psychotherapy of Schizophrenia and other Psychoses in Madrid.