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At What Age Does Mental Illness Begin? The Onset of Mental Illness 

age of mental illness onset

Research shows that the promotion of good mental health and early intervention before or at the onset of mental illness can greatly improve patient outcomes. Parents and loved ones who suspect a child is struggling with mental health should know that these disorders can start at an early age, but that treatment and recovery is possible—especially when caught early on. 

At What Age Does Mental Illness Start? 

According to the National Alliance on Mental Illness (NAMI), the majority of mental illnesses (75 percent) begin by age 24. However, 50 percent of all lifetime mental illnesses begin by age 14. This means that most mental health conditions emerge during childhood and adolescence. 

Another large-scale study, published in 2021 by Molecular Psychiatry, found that the peak age of onset for mental illness was 14.5 years old. The study found that various disorders tend to manifest at different ages. Below is a look at the average age of onset for a range of mental health disorders: 

  • Attention-deficit/hyperactivity disorder (ADHD): 5.5 years old 
  • Anxiety and phobias: 5.5 years old 
  • Obsessive-compulsive disorder: 14.5 years old 
  • Eating disorders: 15.5 years old 
  • Stress disorders: 15.5 years old 
  • Substance addiction: 19.5 years old 
  • Schizophrenia: 20.5 years old 
  • Personality disorders: 20.5 years old 
  • Depression and other mood disorders: 20.5 years old 

This may come as a shock to you, as most people believe that mental illness starts during adulthood. As such, children and adolescents who are showing signs of mental illness often get overlooked, as some parents believe it’s “just a phase” that will pass with time. The truth is, most mental illnesses will surface while a child is still living with their parents – and early intervention and awareness will be key to getting these individuals the help they need and deserve. 

What are the Early Signs of Mental Illness? 

Every mental health disorder will exhibit different signs and symptoms. For example, tell-tale signs of ADHD can include inattention, hyperactivity, and/or impulsivity at a young age. Meanwhile, early signs of anxiety could include a change in sleeping patterns, constant worrying, and/or irrational fears and negative thoughts. It is important to do you research and speak with your pediatrician about any concerning symptoms your child may be exhibiting. To help guide you, we’ve compiled a list of the common signs of mental illness in children and adolescents. These can begin at any age. 

  • Changes in sleeping or eating patterns 
  • Extreme mood swings, potentially including depressed feelings and/or irritability 
  • Withdrawing from family and friends 
  • Avoidance of once-loved activities, such as sports or other hobbies 
  • Drop in grades at school, or skipping school entirely 
  • Difficulty with concentration, learning, or memory 
  • Illogical or irrational thinking 
  • Excessive nervousness or worry 
  • Not wanting to go outside or socialize; also, avoidance of over-stimulating activities 
  • Frequent disobedience, anger, and/or aggression towards others 
  • Inability to sit still, pay attention, or complete a task 
  • Severe risk-taking behaviors and substance use 
  • Lack of self-awareness and a distorted perception of reality 
  • Self-harm or thoughts of suicide 

Click here to learn more about the signs of mental illness in youth. 

What are Common Mental Health Disorders in Children? 

According to the Centers for Disease Control (CDC), the most common mental health disorders in children include attention-deficit/hyperactivity disorder, anxiety, and behavior disorders. Outside of these, children also may develop learning and developmental disabilities, autism, and risk factors like substance abuse and self-harm.  

As children enter the adolescent years, the scope of potential disorders expands. Some of the most common mental illnesses in teenagers include depression, anxiety, OCD, eating disorders, addiction, and stress- or trauma-related disorders. 

These are not hard-and-fast rules, as symptoms of mental health disorders can surface at any age. However, mental illness in young people can typically be spotted when there are behavioral changes, shifts in moods and emotions, and learning difficulties—and these signs are persistent, disrupting their everyday life. 

Mental Illness Can Affect Any Age 

The truth is that mental illness can begin at any age, and affect anyone—no matter their stage of life, socioeconomic status, background or upbringing. However, it is important to recognize that the onset of mental illness is typically during childhood and the teenage years, meaning parents must be educated on the potential signs and risk. While mental illness can be scary, it is highly treatable. Those who seek early treatment for their child can find wonderful outcomes in recovery.  

Children, adolescents, and young adults struggling with mental illness require an age-specific treatment program that specializes in treating early mental health disorders. Young people should be engaged in a treatment program that works with other (and only) youth, so that every child or teen feels comfortable while there. These programs also have staff who are trained in early intervention and youth mental health disorders, and understand the unique needs of children, teens, and young adults. They offer therapies that are recommended for these various age groups, including: 

  • Cognitive Behavioral Therapy (CBT) 
  • Family Therapy 
  • Motivational Interviewing 
  • Individualized Counseling 
  • Group Therapy 
  • Holistic and Recreational Activities (to engage youth in the treatment process) 

These are just some of the many therapies and assets you can find at Turnbridge, a mental health and substance use treatment center for youth. If you would like to learn about our programs, or would like to speak with someone about your loved one’s needs, please do not hesitate to reach out. Call 877-581-1793 today, or explore our programs online

It is never too early to start seeking help for a mental illness.