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Treatment Outcomes for Teen Depression Impacted by Duration and Severity

Written by Evolve's Behavioral Health Content Team​:

Alyson Orcena, LMFT, Melissa Vallas, MD, Shikha Verma, MD, Ellen Bloch, LCSW, Lianne Tendler, LMFT, Megan Johnston, LMFT
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Why Delaying Treatment Can Make Depression Harder to Treat

Depression* is the second most common mental health disorder in the world. According to the World Health Organization (WHO), around 280 million people in the world have clinically diagnosable major depressive disorder (MDD), with depressive states and depression symptoms of depression affecting nearly 350 million worldwide. In addition, the WHO indicates that depression is the leading cause of disability in the world, and the leading contributor to the seven hundred thousand confirmed suicide deaths worldwide each year.

*Anxiety disorders are the most common mental health disorders in the world

The prevalence and consequences of depression in the U.S. mirror those of the prevalence and consequences reported by the WHO. MDD* is the second most common mental health disorder in the U.S. and the leading cause of disability among people age 15-45. Estimates indicate that around 16.1 million (6.7%) adults in the U.S. population have MDD. The average onset of depression – meaning when symptoms first appear – is age 32, but depression can and does develop at any age, including during childhood and adolescence.

*Anxiety disorders are also the most common mental health disorders in the U.S.

Given what we know about depression from its prevalence in the U.S. and the world, it’s crucial for mental health professionals who work with teens, parents of teens, and anyone involved in the life of a teen to understand depression, know why it’s important to seek treatment as soon as they symptoms of depression appear and to get the message that leaving depression untreated can exacerbate the disorder, increase its severity, and lead to extremely negative outcomes, up to an including death by suicide.

To understand why it’s imperative to treat depression – especially in teens – sooner rather than later, we need to know exactly what depression is, according to the experts.

What is Depression?

Let’s start with a simple definition. The Diagnostic and Statistical Manual of Mental Disorders (DSM-V) defines major depressive disorder as:

an overwhelming feeling of sadness, isolation, and despair that last two weeks or longer at a time.”

For an expanded definition and complete discussion of the risk factors and warning signs for depression in teens, please navigate to this helpful and informative article:

Rehab for Teenage Depression: How It Works and Why It Helps

We want to make two relevant points before we share statistics on teen depression in the U.S. and discuss the relationships and interplay between depression severity, duration of depression, the time between the onset of depression and entering treatment depression, and how those factors contribute to or detract from overall treatment success.

Chronic Medical Conditions Like Depression Require Treatment

Our first point is that depression is a medical condition. Our second point is that most forms of depression are chronic, and relapse is not uncommon.

Let’s take a quick moment to talk generally about the difference between chronic illness and acute illness or injury. We’ll start with something very simple, like a cut on your finger. That’s an acute injury. Depending on how bad it is, you might be able to completely ignore it. In some cases, you don’t even need a band-aid. It will heal completely, go away, and never come back. You might be left with a small scar, and that’s it. An acute illness is similar. Take a minor sinus infection, for instance. Depending on how bad it is, you might be able to completely ignore that, too. Most people take medication, but some don’t – and the infection clears up and goes away.

A chronic illness or medical condition is completely different. Think of conditions like asthma, hypertension, diabetes, or something more serious like cancer. If you ignore those conditions, they almost never simply run their course and go away by themselves. Aside from the fact that they respond well to treatment, these chronic conditions are nothing like a cut finger or a sinus infection. When left untreated, they almost always get worse. And the longer they go untreated, the worse and more severe they get. The later treatment starts after initial symptoms appear, the likelihood of relapse after treatment increases.

That’s why we impart a sense of urgency about the diagnosis and treatment of depression: the earlier depression is diagnosed and treated, the better the overall prognosis.

With that in mind, let’s get to the depression prevalence statistics. Then we’ll review the results of the latest studies on the impact of delayed treatment on teen depression.

The Latest Facts and Figures on Teen Depression in the U.S

We collected these statistics from nationwide data published by the Substance Abuse and Mental Health Services Administration (SAMHSA) in their National Survey on Drug Use and Health – 2018.

Depression in Adolescents (Age 12-17)

  • Teens with at least one major depressive episode (MDE) in the past year: 13.84%
    • That’s 3.5 million teens
  • Teens with at least one severe major depressive episode in the past year: 9.7%
    • That’s 2.3 million teens
  • Teens with severe MDE who did receive consistent treatment (7-25 visits per year): 27.3%
    • That’s 614,000 teens
  • As many as 15% of adolescents experience at least some symptoms of depression at any given time
    • That’s about 3.75 million teens
  • For adolescents with depression, an estimated 15% will go on to develop bipolar disorder
    • That’s 525,000 teens

Now we’ll share statistics that foreground the importance of early detection and treatment. These statistics refer to what’s known as the treatment gap, which is the difference between the number of people who need treatment and the number of people who receive treatment. The treatment gap is relevant to our discussion because – as the data we share later will show – the duration and severity of untreated depression has a direct impact on the outcome of treatment.

The Depression Treatment Gap: Adolescents

  • Only 50% of cases of depression that begin during teen years are diagnosed before adulthood
  • Of teens with MDE, 59.6% did not receive treatment of any kind
  • Only 40% of adolescents MDD got the treatment they needed
  • In states with the best access to and most available mental health services, 33% of teens with MDE did not receive any treatment
  • In states with the best access to most available mental health services, fewer than 33% of teens with MDE received consistent treatment
  • Only about 50% of adolescents who begin treatment for mood disorder finish their course of treatment

The treatment gap is a serious problem. We need to recognize that and pay close attention to the mental health of our teens so we can get them the help they need when they need it. We repeat a variation of that phrase over and over in our articles on teen depression, and about teen mental health in general. The sooner a teen diagnosed with depression gets treatment for depression, the better the outcome.

Two recent studies explain why this is the case – and why we keep reminding parents that where treatment for mental health is concerned, sooner is better.

Why Longer Duration and Increased Severity Affect Treatment Outcomes for Teen Depression

We said in layperson’s language above: chronic conditions almost always get worse when they’re left untreated. With conditions such as diabetes and hypertension, we understand the exact physiological mechanisms that make the conditions worse, and lead to an overall deterioration in health the longer they go untreated.

In other words, we know why they get worse. In the case of depression, we now have more information as to why it gets worse over time. The cause is rooted in long-term changes in brain physiology. A study published in 2018 showed the following:

  • Untreated MDD is associated with damage to the physiological structure of the brain
  • Evidence of damage appears in decreased volume in the hippocampus
    • The hippocampus plays a role in:
      • Forming and organizing memories
      • Connecting sensations with memories
      • Connecting emotions with memories
    • Severe symptoms of depression are associated with increased damage to the hippocampus
    • Decreased hippocampal volume – a.k.a. the brain damage – is more severe in patients with a longer duration between the onset of depression and treatment for depression
    • Longer duration between the onset of depression and treatment for depression is also associated with:
      • Poorer clinical outcomes
      • Increased time until symptom relief
      • Increased time until remission

That explains why delaying treatment makes depression harder to treat. Severe, untreated depression can damage the brain – and the damage is both cumulative and progressive.

But that’s not the whole story.

Treatment Works: The Evidence

In contrast, evidence from the same study above shows:

  • Depression treatment is associated with increased hippocampal volume, compared to pre-treatment baseline
  • Medication for depression may slow loss of hippocampal volume loss/prevent additional loss
  • Medication for depression may reverse progressive brain damage related to depression

Evidence from another study, based on the well-known Treatment of Adolescent Depression Study (TADS), shows:

  • Longer duration of symptoms between onset and treatment increase depression severity
  • Longer duration of symptoms between onset and treatment result in poorer treatment outcomes
    • Poorer outcomes mean:
      • Longer time until symptom relief
      • Longer time until remission
    • Increased severity of depressive symptoms resulted in poorer treatment outcomes, i.e. symptom relief and remission
    • Treatment with a combination of medication and CBT was effective for chronic, severe depression
    • Treatment with talk therapy only (cognitive behavioral therapy, or CBT) was less effective for chronic, untreated depression
    • The duration, chronicity, and severity of symptoms were inversely related to treatment success.

We’ll translate that last bullet point for you, and summarize the rest, since they support the entire point of this article. The longer depression goes untreated, the worse the symptoms get, and the worse the symptoms get, the worse they respond to treatment.

However, the data also shows that with a combination of medication and therapy, chronic, severe depression can improve. Adolescents can experience symptom relief, and in some cases, achieve full remission.

Treatment for Teen Depression: The Value of Early Diagnosis and Intervention

Evidence shows that the most effective treatment for teen depression follows the integrated model. The integrated model includes a combination of individual therapy, group therapy, family involvement, community support, and experiential activities combined with lifestyle modification. Treatment success for depression is more than the absence of symptoms: it’s the restoration of total well-being and a sense of purpose in the life of the person with depression.

Here’s how the authors of the article Functional Recovery in Major Depressive Disorder describe the ideal process for the early intervention and treatment of teen depression:

“A collaborative approach to developing and following the treatment plan is needed to achieve goals. The physician and patient should decide together how best to address symptoms and return to pre-illness functioning. The treatment team may also include family members, other clinicians (nurses, social workers, addiction counselors, specialists), and those involved in other aspects of recovery.”

For the greatest chance of treatment success, “early optimized treatment” is essential. This revolves around an accurate diagnosis derived from a full psychiatric evaluation administered by a licensed mental health professional. After diagnosis, the teen, family, and treatment collaborate in the manner described above.

They formulate a plan that leverages the strengths of the teenager, meets the needs of the family, and meets the definition of health and wellness as defined by the teenager themselves. The best treatment plans are dynamic and change as the teen grows and changes on their treatment journey. What works at the beginning might not work six months later. This is true for therapeutic approaches, medication type and dosage, and the lifestyle changes that support recovery.

That’s why open communication between the teen, the family, and the treatment team is paramount. The goal is to learn new skills and move forward, which requires attention and feedback from everyone involved. In the end, evidence of progress – and therefore, evidence of an effective plan – is demonstrated when the teen and their family find balance and harmony, create a new sense of well-being, and return to a level of functioning equal to or better than before the diagnosis of depression.

Finding Help: Resources

If you’re seeking treatment for your teen, please navigate to our page How to Find the Best Treatment Programs for Teens and download our helpful handbook, A Parent’s Guide to Mental Health Treatment for Teens.

In addition, the American Academy of Child and Adolescent Psychiatry (AACAP) is an excellent resource for locating licensed and qualified psychiatrists, therapists, and counselors in your area. Both the National Institute of Mental Health (NIMH) and the National Alliance on Mental Illness also provide and high-quality online resources, ready and waiting for you right now.

Our Behavioral Health Content Team

We are an expert team of behavioral health professionals who are united in our commitment to adolescent recovery and well-being.

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