Psychosis is linked to childhood trauma, study finds

A new study has found a correlation between childhood adversity and symptoms of psychosis, such as hallucinations.

The research, led by Robert Dudley, professor of mental health at the University of York, found that early adversity such as childhood neglect or abuse is associated with an increased risk for psychosis. The study, published in Schizophrenia Bulletin Open, found that people with schizophrenia are 2.72 times more likely to have experienced adverse childhood events than healthy individuals.

Previous research has shown that people with psychosis who also have a history of childhood maltreatment are more likely to experience severe symptoms that do not respond to therapy or medication.

Research has also investigated the role that negative beliefs about self and other people brought on by childhood adversity play in the development of psychotic symptoms, such as paranoia and delusion. Although some have found a relationship, findings so far have been inconsistent.

Dudley and his colleagues collected data from 292 participants (210 males and 82 females) who were part of a larger trial aimed at assessing the efficacy of cognitive behavioural therapy (CBT) for Clozapine-Resistant Schizophrenia (CRS). The majority of participants were white (90%), male (approximately 72%), unemployed (83%) and had a diagnosis of schizophrenia (87%), while 90% had been prescribed clozapine.

The researchers used questionnaires and rating scales to gather information on participants’ experiences of childhood adversity, psychotic symptoms and core beliefs about self and others.

Trauma-focused therapies may help treat psychosis

About one third of participants had experienced abuse and neglect in childhood –  similar to levels reported in other research involving psychosis and childhood trauma. Female participants reported high levels of severe sexual and emotional abuse, consistent with the research literature.

The authors say that their findings are “broadly in line” with an earlier meta-analysis of 23 studies, which found that in people with psychosis the prevalence of self-reported child sexual abuse was 26%, physical abuse 39%, and emotional abuse 36%.  “When adversity is reported, there are often quite noticeable levels of severe to extreme levels that are generally more frequent in females than males, and noticeably so in relation to abuse,” they write.

The findings confirmed that adversity was related to higher levels of psychotic symptoms. “Positive” symptoms, such as hallucinations, were more likely to be influenced by past experiences of childhood adversity. (Hallucinations and delusions are known as “positive” symptoms, while a lack of emotional expression is referred to as a “negative” symptom.)

The study also found a relationship between childhood abuse or neglect and negative beliefs about self and others. Although most of the correlations were fairly modest, the findings are broadly consistent with other research that has found that childhood trauma can lead to individuals with psychosis experiencing distressing symptoms.

The researchers recommend further exploration into the use of trauma-focused therapies, such as eye movement desensitisation and reprocessing (EMDR) in the treatment of psychosis. These would be able to address the underlying factors contributing to psychosis. “Whilst most relationships were modest, they supported previous work indicating that adversity contributes to people with psychosis experiencing distressing symptoms especially hallucinations,” the authors write. “Treatments need to address and target adversity.”

The findings add further evidence to the longstanding debate on causes of psychosis. The current dominant explanation for psychosis is that it is caused largely by genetic factors. The new paper, however, strongly suggests that childhood trauma plays a role in the development of symptoms.