Mental In general, teenagers and young adults are especially vulnerable to depression and anxiety due to the changes to the brain during adolescence. While materially well off, young people today commonly perceive the world in which they live to be highly precarious, complex, and ambiguous, which has a negative effect on their mental well-being. A 2025 survey found that 46% of American Generation Z members had been diagnosed with a mental health condition. A 2020 meta-analysis found that the most common psychiatric disorders among adolescents were
ADHD, anxiety disorders, behavioral disorders, and depression, consistent with a previous one from 2015. While the COVID-19 pandemic has damaged the mental health of people of all ages, the increase was most noticeable for people aged 15 to 24. A 2021
UNICEF report stated that 13% of ten- to nineteen-year-olds around the world had a diagnosed mental health disorder and that suicide was the fourth most common cause of death among fifteen- to nineteen-year-olds. It commented that "disruption to routines, education, recreation, as well as concern for family income, health and increase in stress and anxiety, [caused by the COVID-19 pandemic] is leaving many children and young people feeling afraid, angry and concerned for their future." It also noted that the pandemic had widely disrupted mental health services.
Anxiety over climate change has compounded the problem. Though males remain more likely than females to commit suicide, the prevalence of suicide among teenage girls has risen significantly during the 2010s in many countries. For example, data from the British
National Health Service (NHS) showed that in England, hospitalizations for self-harm doubled among teenage girls between 1997 and 2018, but there was no parallel development among boys. due to a combination of poor
sleep hygiene,
caffeine intake, beds that are too warm, a mismatch between biologically preferred sleep schedules at around puberty and social demands,
insomnia, growing homework load, and having too many
extracurricular activities. Consequences of sleep deprivation include
low mood, worse
emotional regulation,
anxiety,
depression, increased likelihood of
self-harm,
suicidal ideation, and
impaired cognitive functioning. A study by Glasgow University found that the number of schoolchildren in Scotland reporting sleep difficulties increased from 23% in 2014 to 30% in 2018. 37% of teenagers were deemed to have low mood (33% males and 41% females), and 14% were at risk of depression (11% males and 17% females). Older girls faced high pressure from schoolwork, friendships, family, career preparation, maintaining a good
body image and good health. In Canada, teenagers sleep on average between 6.5 and 7.5 hours each night, much less than what the
Canadian Paediatric Society recommends, 10 hours. According to the
Canadian Mental Health Association, only one out of five children who needed mental health services received it. In Ontario, for instance, the number of teenagers getting medical treatment for self-harm doubled in 2019 compared to ten years prior. The number of suicides has also gone up. Various factors that increased youth anxiety and depression include over-parenting, perfectionism (especially with regards to schoolwork), social isolation, social-media use, financial problems, housing worries, and concern over some global issues such as climate change.
Cognitive abilities In many countries, Generation Z youth are more likely to be diagnosed with
intellectual disabilities and
psychiatric disorders than older generations. A 2010 meta-analysis by an international team of mental health experts found that the worldwide prevalence of
intellectual disability (ID) was around one percent. But the share of individuals with such a condition in low- to middle-income countries were up to twice as high as their wealthier counterparts. The researchers also found that ID was more common among children and adolescents than adults. A 2017 study from the Dominican Republic suggests that students from all sectors of the educational system utilize the Internet for academic purposes, yet those from lower socioeconomic backgrounds tend to rank the lowest in terms of reading comprehension skills. A 2020 report by psychologist John Protzko analyzed over 30 studies and found that children have become better at
delaying gratification over the previous 50 years, corresponding to an average increase of 0.18 standard deviations per decade on the IQ scale. This is contrary to the opinion of the majority of the 260 cognitive experts polled (84%), who thought this ability was deteriorating. Researchers test this ability using the
Marshmallow Test. Children are offered treats: if they are willing to wait, they get two; if not, they only get one. The ability to delay gratification is associated with positive life outcomes, such as better academic performance, lower rates of substance use, and healthier body weights. Possible reasons for improvements in the delaying gratification include higher standards of living, better-educated parents, improved nutrition, higher preschool attendance rates, more test awareness, and environmental or genetic changes. Some other cognitive abilities, such as simple reaction time, color acuity, working memory, the complexity of vocabulary usage, and three-dimensional visuospatial reasoning have shown signs of secular decline.
Physical A 2015 study found that the frequency of
nearsightedness has doubled in the
United Kingdom within the last 50 years. Ophthalmologist Steve Schallhorn, chairman of the Optical Express International Medical Advisory Board, noted that research has pointed to a link between the regular use of handheld electronic devices and eyestrain. The
American Optometric Association sounded the alarm in a similar vein. According to a spokeswoman, digital eyestrain, or
computer vision syndrome, is "rampant, especially as we move toward smaller devices and the prominence of devices increase in our everyday lives." Symptoms include dry and irritated eyes, fatigue, eye strain, blurry vision, difficulty focusing, headaches. However, the syndrome does not cause vision loss or any other permanent damage. To alleviate or prevent eyestrain, the
Vision Council recommends that people limit screen time, take frequent breaks, adjust the screen brightness, change the background from bright colors to gray, increase text sizes, and blinking more often. Parents should not only limit their children's screen time but should also lead by example. While
food allergies have been observed by doctors since ancient times and virtually all foods can be allergens, research by the
Mayo Clinic in Minnesota found they have been growing increasingly common since the early 2000s. Today, one in twelve American children has a food allergy, with peanut allergy being the most prevalent type. Reasons for this remain poorly understood. Nut allergies in general have quadrupled and shellfish allergies have increased 40% between 2004 and 2019. In all, about 36% of American children have some kind of allergy. By comparison, this number among the
Amish in Indiana is 7%. Allergies have also risen ominously in other Western countries. In the United Kingdom, for example, the number of children hospitalized for allergic reactions increased by a factor of five between 1990 and the late 2010s, as did the number of British children allergic to peanuts. In general, the better developed the country, the higher the rates of allergies. Reasons for this remain poorly understood. Data from the Australian Bureau of Statistics reveal that 46% of Australians aged 18 to 24, about a million people, were overweight in 2017 and 2018. That number was 39% in 2014 and 2015. Obese individuals face higher risks of type II diabetes, heart disease,
osteoarthritis, and stroke. The Australian Medical Associated and Obesity Coalition have urged the federal government to levy a tax on sugary drinks, to require health ratings, and to regulate the advertisement of fast foods. In all, the number of Australian adults who are overweight or obese rose from 63% in 2014–15 to 67% in 2017–18.
Puberty in girls Globally, there is evidence that girls in Generation Z experienced
puberty at considerably younger ages compared to previous generations, with implications for their welfare and their future. To compound matters, factors known for prompting mental health problems are themselves linked to early pubertal onset; these are early childhood stress, absent fathers, domestic conflict, and low socioeconomic status. Possible causes of early puberty could be positive, namely improved nutrition, or negative, such as obesity and stress. Other triggers include genetic factors, high
body-mass index (BMI), exposure to endocrine-disrupting substances that remain in use, such as
Bisphenol A (found in some plastics) and
dichlorobenzene (used in mothballs and air deodorants), and to banned but persistent chemicals, such as
dichlorodiphenyl-trichloroethane (DDT) and
dichlorodiphenyldichloroethylene (DDE), and perhaps a combination thereof (the 'cocktail effect'). A 2019 meta-analysis and review of the research literature from all inhabited continents found that between 1977 and 2013, the age of pubertal onset among girls has fallen by an average of almost three months per decade, but with significant regional variations, ranging from 10.1 to 13.2 years in Africa to 8.8 to 10.3 years in the United States. This investigation relies on measurements of
thelarche (initiation of breast tissue development) using the
Tanner scale rather than self-reported
menarche (first menstruation) and MRI brain scans for signs of the
hypothalamic-pituitary-gonadal axis being reactivated. == Political views and participation ==