What Defines Severe Mental Illness in Teens?



Severe mental illness is not so clearly defined in most clinical settings. However, most clinicians agree that if a psychological illness lasts in duration (meaning that it is chronic and long-lasting) as well as causes severe disability, then that disorder can be categorized as a severe mental illness (SMI). In addition to severe mental illness, other terms include serious mental illness or persistent mental illness. According to the National Institute of Mental Health, just over 20% of teens (ages 13-18), either currently or at some point during their life, have had a seriously debilitating mental disorder. This equates to about  1 in 5 adolescents.


Teen Severe Mental Illness (SMI) Disorders

Disorders that are commonly considered an SMI include schizophrenia, bipolar disorder, and severe depression. Other serious or severe psychological disorders include:

  • Paranoid and other psychotic disorders
  • Schizoaffective disorders (bipolar or depressive)
  • Pervasive developmental disorders
  • Obsessive-compulsive disorders
  • Depression in childhood and adolescence
  • Panic disorder
  • Post traumatic stress disorders (acute, chronic, or with delayed onset)
  • Bulimia Nervosa
  • Anorexia Nervosa

At the same time, there are some disorders that are considered to be non-serious even though they might be chronic. These include:

  • Personality Disorders
  • Dysthymia Disorder (also known as Persistent Depressive Disorder)
  • Cyclothymic Disorder (numerous periods of hypomanic symptoms interspersed with periods of depressive symptoms)
  • Seasonal Affective Disorder (SAD)
  • Generalized Anxiety Disorder
  • Acute Stress Disorder
  • Adjustment Disorder
  • Adjustment Disorder with depressed mood
  • Attention Deficit / Hyperactivity Disorder (ADHD)
  • Social Phobia
  • Dissociative Identity Disorder

Furthermore, it’s important to point out that various groups sometimes define severe mental illness for different reasons. For instance, there might be legal reasons, clinical reasons, epidemiological reasons and reasons related to medical insurance coverage. Depending upon who is defining an illness, it may or may not be considered an SMI. Currently, there is no standard definition of SMI, only a general consensus of illnesses that are chronic and severely debilitating.


Schizophrenia in Teens

However, one clear cut example of an SMI disorder is schizophrenia. This is a psychological illness that affects thinking, feeling, movement, and behavior. It is characterized by a break in reality known as psychosis, which often includes experiencing hallucinations or delusions. Symptoms of schizophrenia are clinically divided into three main categories: positive, negative, and cognitive. Typically, schizophrenia shows up in late adolescence. In order for a teen to be diagnosed, the following symptoms must last longer than six months.


Positive symptoms are those that become present and would not normally occur without the illness, such as certain sensations, beliefs, and behaviors. They include disturbances in thought, delusions, hallucinations, certain erratic feelings, changes in movement, and unusual behavior. Psychosis makes up a major part of the positive symptoms. It is considered to be an experience of the mind (psyche) characterized by the loss of contact with reality and including either hallucinations or delusions


Negative symptoms are the absence of certain abilities. These can include low energy, low motivation, poor social skills, little facial movements, and less than lively physical movement. Although these might seem less significant than those listed above, a loss of energy and motivation can also have a significant impact on a teen’s life, particularly at this stage in life.


Cognitive symptoms refer to difficulty with concentration and memory, such as disorganized thinking, slow thinking, difficulty understanding, poor concentration, poor memory, difficulty expressing thoughts, and having a hard time integrating thoughts with feelings and behavior.


Early warning signs of psychosis can include:

  • drop in grades or job performance
  • trouble thinking clearly or concentrating
  • paranoia or suspiciousness
  • uneasiness with others
  • decline in self-care or personal hygiene
  • spending a lot more time alone than usual
  • increased sensitivity to sights or sounds
  • mistaking noises for voices
  • having unusual ideas
  • having strange feelings or having no feelings at all

Schizophrenia and other types of psychotic disorders are quickly categorized SMI because these are life-long illnesses with severe disabilities. Fortunately, there are treatment modalities that can help ease an adolescent’s struggle with the illness. In fact, many who are diagnosed with schizophrenia can go on to live normal lives, as long they continue to engage in treatment.


Teen Bipolar Disorder

Bipolar Disorder is also typically categorized as an SMI. Bipolar is a mood disorder characterized by a mood swings between depression and mania. Unlike depression (such as major depressive disorder), bipolar disorder (bi meaning two) is characterized by the swing of moods between mania and depression, moving between both poles. When a teen with Bipolar Disorder experiences depression, they might experience these symptoms:

  • Lasting sad, anxious, or empty mood
  • Feelings of hopelessness or pessimism
  • Feelings of guilt, worthlessness, or helplessness
  • Loss of interest or pleasure in activities
  • Loss of interest in sexual activity
  • Decreased energy or fatigue
  • Difficulty making decisions, concentrating or focusing
  • Difficulty in memory
  • Restlessness or irritability
  • Oversleeping
  • Sudden weight gain or loss
  • Suicidal ideation

In addition to the symptoms of depression listed above, a teen might also experience mania which can come with these symptoms:

  • Increased energy, activity, and restlessness
  • Excessively “high”, euphoric mood
  • Extreme irritability
  • Racing thoughts and talking very fast, jumping from one idea to the other
  • Distractibility – an inability to concentrate
  • Unrealistic beliefs about one’s abilities
  • Poor judgment
  • Spending sprees
  • Increased sex drive
  • Little sleep
  • Provocative, intrusive, or aggressive behavior
  • Denial that anything is wrong

Because Bipolar Disorder can be challenging for teens, it’s common for them to turn to unhealthy coping tools, such as substance use, self-injury, and other risky behavior as a means for numbing emotional pain. However, as with Schizophrenia, there are treatment methods that can help ease the challenges that come with this disorder.


Severe Depression in Teens


Like Schizophrenia and Bipolar Disorder, depression can also be a chronic and debilitating disorder. Depression is a mood disorder, often causing low energy, sadness, and suicidal thinking. Approximately,  14% of 13 to 18 year olds experience mood disorders and 4.7% of teens experience a severe mood disorder, such as severe depression.


What makes severe depression debilitating is the risk of losing someone to suicide. Because severe depression can cause suicidal thinking, teens might act out on their thoughts and attempt to take their life. In fact, currently, suicide is the third leading cause of death among teens.


Fortunately, there is treatment for depression that is effective for most teens. Typically, when a teen is diagnosed with depression, they are treated with medication and psychotherapy. There are various forms of antidepressants that can help lift depressive symptoms. When medication is used to treat depression, there is a 50% reduction in symptoms within 8 to 12 weeks. Approximately 60% of teens show a significant clinical response by 12 weeks and remission by 24 weeks. Furthermore, regular exercise, healthy eating, and building a support network can help a teen overcome depression.


Treatment Resistant Depression

However, in some cases, medication and psychotherapy may be ineffective. Approximately, 40% of teens who receive treatment for their depression are considered to be treatment resistant. Treatment resistant depression, which is depression that does not respond to the treatment that has been consistently effective with other teens, can contribute to severe mental illness. Obviously, when a teen does not respond to treatment, depression can become chronic. As treatment continues to be ineffective, this can worsen symptoms and undermine the hope a teen has. There are some factors that seem to consistently contribute to chronic depression and treatment resistance. They are:

  • Severity of depression
  • Co-occurring disorders, especially substance use
  • Non-adherence to treatment
  • Low blood concentration of the antidepressant
  • History of abuse
  • Parental depression
  • Bullying at school

To work with severe depression in teens, be sure to have your teen thoroughly examined in order to uncover any factors that might be contributing to the treatment resistance. For example, issues that might be explored in detail include quality of sleep, other psychological issues, and health factors. Treatment might be augmented, giving remission another chance. In other cases, different medication types might be explored. For instance, those who have not responded to traditional forms of treatment can undergo a treatment plan that uses a different type of antidepressant (such as SSNRI, TCA’s or MAOI’s) and a different form of therapy. Over time, with some trial and error, clinicians might find the right treatment plan for a teen to help them overcome the illness of depression.


SMI Requires Professional Help

If your teen has been experiencing the symptoms of a disorder for many months and if your adolescent is struggling to function in their day because of it, it’s important to seek out a mental health professional. If you’d like to learn more about severe mental illness or the specific illnesses described above, visit the website for the National Alliance on Mental Illness.

More importantly, if your teen is experiencing mental health emergency, such as causing imminent harm to themselves or others, you must call 911 or bring your teen to the nearest hospital. The illnesses listed above can be fatal in some circumstances. If you feel your teen is experiencing the symptoms of a severe mental illness, call for help today.



Do you have experience with severe mental illness? If so, what steps have you taken to manage your mental health disorder? Share your story in the comments below and any tips that might be helpful for others dealing with a similar illness.