Chapter 93. Risks and Rates of Disorders

1. Measuring the prevalence of psychological disorders is not an easy task. Reported rates vary significantly from country to country, with countries having strong mental health services and better recordkeeping generally reporting higher prevalence of disorders. However, as this map shows, rates of some disorders (such as mood disorders) are generally higher in regions with high conflict and/or low economic opportunities.

2. The rates for many disorders also vary by sex. Females are more likely to experience mood disorders and anxiety disorders, while males are more likely to experience substance use disorder and one of the personality disorders called antisocial personality disorder. The likelihood of developing schizophrenia and dissociative disorders appears to be similar for males and females.

3. Researchers estimate the risk of developing a psychological disorder in two different ways. The rate per year for a disorder refers to the estimated percentage of adults who will experience that disorder in any given year (that is, at some point during the next 12 months). This annual risk may hold steady or even drop with age, as is the case with mood disorders. The rate over a lifetime for a disorder refers to the estimated percentage of adults who will experience that disorder at some point in their lives. As the graph shows, this lifetime risk goes up with age.

4. Although every person is potentially vulnerable to a psychological disorder at some point in life, researchers have identified a set of risk factors that make a disorder more likely. Any type of physical or mental impairment increases the risk, as does growing up in a dysfunctional or abusive family, especially if the family is very poor. However, the experience of significant, sustained traumatic events seems to be the single largest risk factor for psychological disorders.