Forgetfulness can hurt teenagers if it causes them to skip medications or do poorly in school. Reasons why teens may be forgetful affect adults as well: depression, dyslexia, attentional disorders, hypothyroidism, sleep deprivation and substance abuse. However, before concluding that your child has a serious problem, consider that organizational abilities improve as teens mature. Absentmindedness may also be oppositional behavior in response to nagging -- faux forgetfulness.
Depression
Teens have less life experience than adults. They are just beginning to develop coping skills for responding to troubling situations, so difficulties may weigh on them more than adults realize. Depression or anxiety can also cause short-term memory loss and difficulty concentrating. It notes that other signs of depression include withdrawal from family, friends and favorite activities as well as changes in grades and sleep patterns.
Dyslexia
Dyslexia involves academic difficulties with reading, spelling and writing. But it can also be a cause of disorganization and forgetfulness. Dyslexic teens may experience short-term memory lapses that make it difficult to remember telephone numbers, follow lists of instructions and take notes in school. They may appear forgetful by losing track in conversations or not hearing everything that is said.
Attentional Disorders
Teens who have learning disabilities or attention deficit disorders may be forgetful due to a shortage of "executive function" skills. Executive functions include the abilities to remember, organize and complete tasks. They also help teens connect past experiences to choices made in the present. Teens who have delays in executive-function development may also make bad social choices due to forgetting past learning experiences.
Hypothyroidism
People of all ages, from infancy to old age, may experience memory problems due to hypothyroidism, or an underactive thyroid gland. MayoClinic.com says that thought processes slow when hypothyroidism is untreated. It notes that teens generally have the same symptoms as adults, which include fatigue, sluggishness, dry skin, brittle hair, weight gain and increased cholesterol. However, teen symptoms may also include poor growth, slow development of permanent teeth, delayed puberty and poor mental development.
Sleep Difficulties
Poor sleep habits, such as repeatedly going to bed late despite having to wake up early, interfere with memory. But teen sleep deprivation can also be caused by more serious problems, such as depression, insomnia or narcolepsy, a disorder causing a person to fall asleep at inappropriate times. Another disorder, sleep apnea, which causes loud snoring and a temporary halt to breathing during sleep, causes daytime drowsiness that makes it difficult to concentrate and remember.
Substance Abuse
Severe forgetfulness may also be a warning signal that a teen is taking illegal drugs or developing a drinking problem. Marijuana particularly affects short-term memory loss. Other symptoms of substance abuse include extreme low energy and disengagement.
References
- Dyslexia Parents Resource; Teenagers and Dyslexia; S. Moody
- Smart Kids With Learning Disabilities; Adolescents and Executive Function Skills; Eve Kessler, Esq.,et al.
- Education.com: What Is Executive Function?
- MayoClinic.com; Hypothyroidism (Underactive Thyroid); June 2010
- News Medical; Adolescents Who Are Lethargic, Cranky and Forgetful... Sleep Deprivation; June 2005


