Mental illnesses are among the most common health conditions in the United States.
The National Alliance on Mental Illness reported in June 2022 that one out of five U.S. adults experience mental illnesses each year.
At the same time, one in every 20 U.S. residents live with a serious mental illness.
That totals to more than 16 million people in the U.S. living with a serious mental illness including schizophrenia, bipolar disorder or major depression, according to the National Alliance Mental Illness report.
San Jose State psychology professor Elena Klaw said there are significant factors to consider to recognize mental health illnesses.
“When we call something a disorder, it has to fit two criteria,” Klaw said. “One is significant distress and the other is functional impairment.”
Anxiety Disorders
The most prevalent mental illnesses in the U.S., affecting about 42 million people, are anxiety disorders, according to the National Alliance on Mental Illness Anxiety Disorder webpage.
Anxiety disorders include those that share features of excessive fear and anxiety and related-behavioral disturbances, according to the Diagnostic and Statistical Manual of Mental Disorders website.
U.S. healthcare professionals use the Diagnostic and Statistical Manual of Mental Health as the authoritative guide to mental disorder diagnoses, according to the American Psychiatry Association website.
SJSU psychology assistant professor Lesther Papa said anxiety itself is not a disorder.
“There are normal amounts of anxiety and stress that someone can experience and still be functional,” Papa said.
Anxiety is often associated with muscle tension and vigilance in preparation for future danger and cautious or avoidant behaviors, according to the Diagnostic and Statistical Manual of Mental Disorders.
Klaw said when anxiety becomes disabling, it impairs functional activities, causing significant distress.
“It's a disordered way of relating to the world – when we go into that category where we're feeling that our way of relating to the world has become disordered, we benefit from psychological and psychiatric help.”
There are also scenarios in which anxiety levels impair people’s functional activities leading to other mental illnesses.
For instance, Papa said anxiety can lead to depression.
“You might have . . . some social anxiety that's not necessarily disordered but it's a struggle for you to meet somebody new and to be able to talk with people to be able to maintain the types of friendships that you want,” Papa said. “So that contributes to feeling lonely and that loneliness then contributes to you feeling depressed.”
Depression
Klaw said when depression is at a chronically low-level state, experts call it dysthymia.
Dysthymia is a milder but long-lasting form of depression. It’s also called persistent depressive disorder, according to the National Institute of Mental Health.
Klaw said a second form of the disorder, characterized by an individual’s severe impairment, is called major depression.
There are 21 million U.S. residents who have major depression, and it can result in severe impairments capable of interfering or limiting a person’s ability to carry out major life activities, according to the National Institute of Mental Health Major Depression webpage.
Among depression’s symptoms, there is at least a two-week period during which a person experiences a depressed mood or loss of interest or pleasure in daily activities, according to the webpage.
Papa said there are biological and genetic factors that could influence depression.
“Starting with the biological [factor], some people are just born with a little bit of a predisposition to developing depression, either genetically, right? They are at risk because they have a family history of depression,” Papa said.
However, there are more components capable of influencing depression.
Papa said neurotransmitters also play an important role because they modulate people’s moods.
Neurotransmitters are endogenous chemicals allowing neurons to communicate with each other throughout the body and are integral in shaping everyday life and functions, according to a National Library of Medicine May 8, 2022 article.
“Specifically, things like serotonin and dopamine, right? These neurotransmitters may not be already at an optimal level for somebody,” Papa said. “And so it makes them more at risk for developing depression.”
Bipolar Disorder
Bipolar disorder, also referred to as manic-depressive disorder, is characterized by shifts in mood, energy and activity levels that affect a person’s ability to carry out daily tasks, according to the National Institute of Mental Health Bipolar Disorder webpage.
There are about six million people in the U.S. who have bipolar disorder, according to the webpage.
Klaw said a person who has bipolar disorder experiences both depression and manic cycles.
“You experience both depression, these disappear, disabling lows, and manic is a feeling of a high, right? That can be so extreme that people stop eating and sleeping,” she said.
The cycles of depression and manic length may vary and the disorder can be chronic or episodic. An individual who has the disorder may have manic, depressive or “mixed” episodes, according to the same National Institute of Mental Health Bipolar Disorder webpage.
Klaw said everyone experiences ups and downs in their moods, but with bipolar disorder, the range of mood changes can be extreme.
People who have this mental illness have manic episodes or unusually elevated moods in which the individual might feel very happy, irritable, with a marked increase in activity level, according to the same National Institute of Mental Health Bipolar Disorder webpage.
“Let's keep in mind that people have genetic vulnerabilities to these disorders,” Klaw said. “So, unlike everyday’s sadness, which everybody can experience, bipolar is heavily genetic, meaning that one might have a vulnerability to that mood disorder.”
PTSD
Post-traumatic stress disorder is a mental illness that develops in some people who have experienced a shocking, scary or dangerous event, according to the National Institute of Mental Health PTSD webpage.
Papa said when talking about PTSD, it is important to identify the trauma that triggers the mental illness.
“In order to get that diagnosis of post-traumatic stress disorder, that traumatic event has to involve death, it has to involve serious injury or it has to involve sexual violence,” he said.
About 6% of the U.S. population will have PTSD at some point in their lives, according to the U.S. Department of Veteran Affairs webpage.
However, not all traumatic events generate PTSD.
“You can have traumatizing incidents that can make life challenging for you, but there's no PTSD,” Papa said. “So the things that influenced them, like whether or not trauma will influence your life, depends on if those events then lead to a cluster of symptoms.”
Klaw said one of the symptoms related to PTSD is chronic hyperarousal.
With hyperarousal, individuals who have PTSD can live in states of constant tension and their fight-or-flight responses are perpetually turned on, according to a May 18, 2021 WebMd article.
Klaw also said adrenaline and cortisol are the two neurotransmitters correlated to the hyperarousal symptoms.
“They're pumping all the time because it's that ‘Fight or flight,’ ” Klaw said. “So let's say you're a military veteran, you were deployed, you went to war, you learn to keep yourself hyper-aroused and hyper-vigilant all the time, because that's how you stay safe.”
