Symptoms of psychosis were associated with greatly increased risk for suicidal behavior in the general adolescent population as well as in adolescents who have nonpsychotic disorders, such as depression, attention-deficit/hyperactivity disorder, anxiety disorders, or obsessive compulsive disorder, according to two separate epidemiologic studies reported online Oct. 29 in the Archives of General Psychiatry.

Among adolescents in the general population, as well as the subgroup of adolescents who had nonpsychotic DSM-III diagnoses, those who reported suicidal ideation, suicide planning, or suicidal acts were 10 times more likely than those who did not to affirm on direct questioning that they had experienced psychotic symptoms – mainly auditory hallucinations, said Ian Kelleher, Ph.D., of the department of psychiatry, Royal College of Surgeons in Ireland, Dublin, and his associates.

“The immediate clinical relevance of these findings is that all patients presenting at risk for suicidal behavior should receive a thorough assessment of psychotic symptoms and not just a screening to rule out psychotic disorder,” they noted.

Both primary care physicians and psychiatric clinicians must recognize that psychotic symptoms in a nonpsychotic patient signify a high suicide risk. “Research has shown that the largest increase in suicide risk in the general population occurs after there has already been contact with mental health services and that approximately half of patients who complete suicide [had] contact with primary care providers in the month preceding their death[s],” the investigators added.

Hallucinations and delusions, the classic symptoms of psychosis, are far more prevalent in the general population than are diagnosable psychotic disorders. They are “especially common in young people, with a meta-analysis of general population studies demonstrating a median prevalence of 17% in children aged 9-12 years and 7.5% in adolescents aged 13-17 years,” the researchers wrote.

And psychosis is known to raise the risk of suicide dramatically. Yet no studies to date have examined the relationship between psychotic symptoms and suicidal behaviors among adolescents. Dr. Kelleher and his colleagues did so using data from two independent cross-sectional epidemiologic studies of the general Irish population.

The Adolescent Brain Development (ABD) study assessed the prevalence of psychotic symptoms among 1,131 students aged 11-13 years in 16 mainstream schools, representing more than half of the total school population in that age group. The Challenging Times (CT) study assessed the prevalence of psychiatric disorders among 743 students aged 13-15 years in eight mainstream schools.

For this study, Dr. Kelleher and his associates analyzed the results of in-depth diagnostic interviews for 212 subjects from the ABD study and 211 from the CT study, as well as the interview responses of their parents.

Overall, 22% of the ABD sample and 7% of the CT sample reported experiencing psychotic symptoms when they were specifically asked about them, almost all of them during the preceding year. “From our clinical experience, young people will rarely volunteer information on psychotic symptoms unless questioned directly about such experiences. Adolescents are usually willing to talk openly about their experiences, however, in response to direct but sensitive questioning.”

Examples of such questions included: “Sometimes people when they are alone hear things or see things, and they’re not quite sure where they came from. Does that ever happen to you?” and “Was there ever a time when you thought that your imagination was playing tricks on you?”

In the two cohorts combined, 44 subjects reported suicidal ideation, 16 reported making specific suicidal plans, and 8 reported suicidal acts.

Adolescents in both studies who reported suicidal behavior were more than 10 times more likely than were those who did not report suicidal behavior to say that they had also experienced hallucinations or delusions, the investigators said (Arch. Gen. Psychiatry Oct. 29 [doi:10.1001/archgenpsychiatry.2012.164]).

“Strikingly, a majority of adolescents with suicidal plans or acts reported psychotic symptoms in both the ABD study (60%) and the CT (55%), studies,” they noted.

The researchers also examined the link between psychotic symptoms and suicidal behavior in the subgroup of adolescents who had a diagnosable psychiatric disorder. These included major depressive disorder, adjustment disorder with depressed mood, ADHD, oppositional defiant disorder, conduct disorder, generalized anxiety disorder, social phobia, separation anxiety disorder, and OCD.

In these high-risk subjects, those who reported experiencing hallucinations or delusions were more than five times more likely to also report suicidal behavior than were subjects who had no psychotic symptoms.

Moreover, a further analysis of the data showed that adolescents who had psychotic symptoms were more likely to show the most serious suicidal behavior (planning and attempts) than the less serious suicidal ideation.

This study was not designed to examine the reasons for this robust association between psychotic symptoms and suicidal behavior, but there are several possible mechanisms.

“The most obvious is that hallucinations may direct the individual to harm or kill themselves.” However, only one subject reported hearing a voice commanding him to do so, suggesting that the content of hallucinations is not to blame, at least not in this age group.

Indirect cognitive mechanisms may play a role. “Changes in the subjective sense of self, for example, are among the earliest recognizable symptoms of psychosis, and a sense of disintegration and fragmentation of the self resulting from intrusive voices or thoughts have been linked to suicidal thinking,” Dr. Kelleher and his colleagues said.

Alternatively, “Bleuler’s concept of ‘the suicidal drive’ might not be just the most severe symptom of schizophrenia but the most severe symptom of a much broader psychosis phenotype made up of individuals in the general population who experience psychotic symptoms,” they wrote.

It is also possible some common factor underlies both psychotic symptoms and suicidal behavior. For example, the symptoms may be a marker for deteriorating mental health, which in turn puts patients at high risk for suicide.

Traumatic experiences also might be an underlying factor. Adolescents who have experienced severe adverse events such as childhood physical or sexual abuse are known to be at increased risk for developing psychotic symptoms, and their psychological distress may also place them at high risk for suicidal behavior, the researchers said.

This study also could not delineate when psychotic symptoms arose in relation to suicidal behavior, because it was cross-sectional rather than longitudinal. “Further research with more temporal information will help to address this point,” they added.

This study was funded by the European Community’s Seventh Framework Programme. No conflicts of interest were reported.