Psychotic experiences in general populations are common; a meta-analysis based on 61 studies in very diverse countries worldwide reported that a median lifetime prevalence in general populations of 7.2%. [1]. This prevalence is substantially higher than the lifetime risk for psychotic disorders, such as schizophrenia, and these experiences encompass both hallucinatory experiences (HEs) and delusional experiences (DEs) that do not rise to the level of clinical thought disorder diagnoses. [1]. However, most studies describing the prevalence of PEs have been collected in high income countries [1], which may represent variations in prevalence and correlates compared to low income and conflict-associated countries, among which the majority of the world’s population reside.
To fit that gap, a large survey of 256,445 participants from nationally representative samples of 52 low income countries worldwide was launched by the World Health Organization: overall prevalence for specific PEs ranged from 4.80% for delusions of control to 8.37% for delusions of reference and persecution [2]. Prevalence figures varied greatly across countries from 0.8–31.4%. All psychotic symptoms were associated with a significant decline in health status after controlling for potential confounders; there was a clear difference in health between subjects not reporting any symptom and those reporting at least one such symptom.
Another consortium, the World Mental Health Surveys, coordinated a set of community epidemiologic surveys of the prevalence and correlates of mental disorders in representative household samples from 18 countries across the world, and included 31,261 adults (18 years and older), from a low to high income level groups, who were queried regarding lifetime and 12-month prevalence and frequency of 6 types of PEs (2 hallucinatory experiences and 4 delusional experiences) [3]. Mean lifetime prevalence of ever having a PE was 5.8%, with HE (5.2%) more common than delusional experiences (DE, 1.3%). More than two-thirds (72.0%) of respondents with lifetime PEs reported experiencing only 1 type of the listed PE. PEs lifetime prevalence estimates were significantly higher among respondents in middle- and high-income countries than among those in low-income countries: 7.2%, 6.8% and 3.2% respectively. However, inter-country differences were wide, from 14.9% in urban Brazilian samples and 10.8% in the Netherlands, to 1% in Romania, 1.2% in Iraq and 1.9% in Lebanon. PE were more frequent among women than among men (6.6% vs 5.0%), and those who were unmarried, unemployed and with lower household income level [3]. DE were more likely to be reported than HE by younger respondents, and migrants reported lower HE then non-migrants. Religiosity, defined as attributing importance of religious beliefs in daily life, in making decisions, seeking comfort when experiencing problems or importance of religion when growing up, was found to be positively associated with PE [4] and did not differ across the variety of religious affiliations .
Moreover, the wide range of countries allowed examination of cause and consequences of PE, confirming that PEs are linked to poor health and psychiatric comorbidity. PEs have been found to be associated independent of comorbid mental disorders with the subsequent onset of a wide range of medical conditions (arthritis, back or neck pain, frequent or severe headache, other chronic pain, heart disease, high blood pressure, diabetes, and peptic ulcer). Further, three medical conditions (frequent or severe headache, other chronic pain, and asthma) were significantly associated with subsequent onset of PEs.[5]. PEs have also been found associated to suicidal thoughts and behaviors (STB): respondents with one or more PEs had two-fold increased odds of subsequent STBs after adjusting for antecedent or intervening mental disorders. There were significant dose-response relationships of number of PEs types with subsequent STBs that persisted after adjustment for mental disorders [6].
Temporal associations between mental health disorders and PEs have been found to be more complex and bidirectional [7]: while temporally primary PEs are associated with an elevated risk of several subsequent mental disorders, with odd ratios ranging from 1.3 for major depressive disorders to 2.0 for bipolar disorder, most mental disorders are associated with an elevated risk of subsequent PE ranging from 1.5 for childhood separation anxiety to 2.8 for anorexia nervosa.
Associations between PEs and substance use/substance use disorders (SU/SUDs) have also been found to often be bidirectional, but not all types of SU/SUDs are associated with PEs [8]. Those with prior alcohol use disorders, extra-medical prescription drug use, alcohol use and tobacco use had increased odds of subsequent first onset of PEs. In contrast, those with temporally prior PEs had increased odds of subsequent onset of tobacco use, alcohol use or cannabis use as well as of all substance use disorders. There was a dose response relationship between both count and frequency of PEs and increased subsequent odds of selected SU/SUDs.
Ultimately, PEs have been found to be associated with disability measures in a dose–response relationship regardless of the presence of comorbid mental or general medical disorders [9]. Respondents with PEs were more likely to have top quartile scores on global disability than respondents without PEs: 19.1% vs. 7.5% as well as greater likelihood of cognitive, social, and role impairment. The association between PEs and aspects of health-related quality of life as measured by Health-related quality of life (HRQoL), a self-rated physical or mental health, was also investigated [10], with those with a history of PEs at increased odds of poor perceived mental and physical health after adjustment for the presence of any mental or general medical conditions.
In addition, the WMH surveys allowed the study of transnationally trauma and PEs. In assessing 29 traumatic experiences, respondents with any traumatic event had three times the odds of subsequent developing PEs, with variability in strength of association across traumatic event types. This association persisted after adjustment for mental disorders including PTSD [11].
Since the Afghan population has been subjected to significant trauma [12], as 48.76% of the population reported four or more events including witnessing war and conflict related violence, it is then important to evaluate the presence and frequency of such PEs and their associations with physical and mental disorders in that context, given the heightened exposure to risk factors.
Therefore, we utilized a large nationally representative survey of the general population of Afghanistan to evaluate 1) the detailed prevalence of PEs by type (HEs and DEs) and their respective frequency 2) their main sociodemographic association including ethnic subgroups and locations/regions 3) their associations with psychiatric disorders including major depressive episode, generalized anxiety, PTSD, addictions and suicidal behaviors 4) their relative associations with types of trauma, and 5) their associations with demographics, ethnicities and income