The Impact of Depression on Mental Health

Depression, as a heterogeneous collection of disorders, is likely to include subgroups that are more genetic in origin. In common with other neuropsychiatric disorders such as schizophrenia, Alzheimer’s disease and Huntington’s disease, earlier age at onset in depression is associated with higher genetic loading and poorer long-term outcome. Adolescents and young adults with depression are also at high risk of developing a bipolar illness. This article reviews depressive illnesses that occur for the first time in adolescence and young adulthood. Case studies are used to discuss atypical presentations and the evolving concept of bipolar-spectrum disorders.

Affective illnesses may present at any age, but it is becoming clear that patients who suffer from recurrent and severe forms of mood disorder often experience their first episode of illness early in life. The clinical presentation of depression at this stage of life can be atypical and is often complicated by personality difficulties and substance misuse. A significant proportion of young people presenting with recurrent depression will go on to develop a bipolar disorder, with important implications for future pharmacological treatment choices.

• In UK suicide is most common cause of death among young men ages 25-34. Risk factors include poor schooling, poverty, unemployment, history of mental illness and family history of mental illness and suicide.
• Study of young people who died by suicide (age 115-24) found 70% suffered from previous mental illness – mostly depression (56%).  Another 30% had personality disorder and 33% had more than one disorder. Very few receiving psychiatric care when they died.
• Most surveys suggest 5% of adults suffer from depression, but Finnish study suggests 10% of teens – with very few receiving treatment.
• Teens with “sub-diagnostic” depression more likely to develop adult depression, substance misuse and poor social functioning.
• Long term study of 149 people who suffered adolescent depression found 62% suffered major depression as adults and 44% attempted suicide at least once.
• Girls twice as likely to suffer depressions, even though boys slightly more likely before puberty.
• 15-year follow up of 74 young adults hospitalized for depression found 27% developed hypomania plus 19% with at least one episode.  Bipolar preceded by depression in eight out of 10 patients.
• Genetics accounts for 32%-42% of the risk, but repeated severe early depression 70% linked to genetics – similar to bipolar.
• Neuroticism (neurotic stress breakdown) also highly linked to genes – and strongly linked to depression. Complicated interaction between neurotic and depressed. Young people prone to neuoticism more likely to place themselves in high-risk situations, but are less able to deal with stressful life events and so more likely to develop depression. Initially, the depressive episodes are linked to events – but become increasingly decoupled.
• Early life trauma clearly linked to depression, but genetic factors may affect vulnerability to those traumatic events.
• Early life stress and depression interact – people in depression more likely to generate stressful events and have a harder time dealing with those events.
• Substance misuse: Drug and alcohol use risk factors – and affect the long-term course of depression. Adolescents who experience depression more likely to develop alcohol or drug use problems later in life – and vice versa. So early depression an opportunity for intervention. 
• Cannabis use: Studies already show link to psychotic disorders – but evidence growing that it’s also a risk factor – of associated with – depression. Still unclear as to cause and effect. Several studies now suggest that daily use of cannabis between ages of 14 and 21 are a risk factor for anxiety and depression in early adulthood – especially for girls, who had fve times the risk of depression as non-users. Second study found the younger age (14-27) with daily cannabis use were much more likely to later develop depression – suggesting there’s a certain age at which cannabis most strongly affects the brain.
• Early alcohol use predicts depression, substance abuse and alcohol abuse before the age of 27.

National Institutes of Health

Topics page on depression: based on 2021 national survey on drug use and health

• An estimated 21.0 million adults in the United States had at least one major depressive episode. This number represented
• 8.3% of all U.S. adults.
• The prevalence of major depressive episode was higher among adult females (10.3%) compared to males (6.2%).
• The prevalence of adults with a major depressive episode was highest among individuals aged 18-25 (18.6%).
• The prevalence of major depressive episode was highest among those who report having multiple (two or more) races (13.9%).
• In 2021, an estimated 61.0% U.S. adults aged 18 or older with major depressive episode received treatment in the past year.
• Among those individuals with major depressive episode with severe impairment, an estimated 74.8% received treatment in the past year.
• In 2021, an estimated 3.7 million adolescents aged 12 to 17 in the United States had at least one major depressive episode with severe impairment in the past year. This number represented 14.7% of the U.S. population aged 12 to 17.
• In 2021, an estimated 40.6% of U.S. adolescents with major depressive episode received treatment in the past year.
• Among adolescents with major depressive episode with severe impairment, an estimated 44.2% received treatment in the past year.

World Health Organization: 

Globally, one in seven 10-19-year-olds experiences a mental disorder, accounting for 15% of the global burden of disease in this age group.

Depression, anxiety and behavioural disorders are among the leading causes of illness and disability among adolescents.

Suicide is the third leading cause of death among those aged 15–29 years old.

The consequences of failing to address adolescent mental health conditions extend to adulthood, impairing both physical and mental health and limiting opportunities to lead fulfilling lives as adults.

Emotional disorders are common among adolescents. Anxiety disorders (which may involve panic or excessive worry) are the most prevalent in this age group and are more common among older  than among younger adolescents. It is estimated that 4.4% of 10–14-year-olds and 5.5% of  15–19-year-olds experience an anxiety disorder (1). Depression is estimated to occur among 1.4% of  adolescents aged 10–14 years, and 3.5% of 15–19-year-olds (1). Depression and anxiety share some of the same symptoms, including rapid and unexpected changes in mood.

CDC: Depression in adults 18 years old: 

• 18.4% of US adults report lifetime depression diagnoses – ranging from 13% in Hawaii to 28% in West Virginia by state and fro 11-32% by county (especially Appalachia)
• Depression for women: 24% vs men 13%
• Non-hispanic white: 22% vs 15% bHispanic/ladino: 16% black, Asian: 7%, less than high school 21%, high school ed 19%  college ed 15%
• In 2020- one in five have a history of depression, 
• Protective factors: physical activity, quality sleep, good nutrition
• Co-morbidityi with diabetes, arthritis, cardiovascularRou