Mood Disorders

Mood is defined as the experience of a feeling.

Feelings are emotional experiences that influence our life. Moods Opens in new window impact our behavior, how we think and feel, and shape our emotional experience of the world.

To be human is to experience an array of different emotions. We can feel upbeat and hopeful, cool and unconcerned, or frustrated and fearful in a given day—even in a given moment.

The heart of human experience beats with moments of joy and flashes of sorrow, and with textures of less potent emotions sprinkled in-between.

When our moods ease back and forth along this continuum, we experience a healthy sense of well-being. Most people have good days and bad days, and persevere without becoming sidelined. However, there are individuals whose moods crescendo to an overexcited state, plummet toward a hopeless abyss, or cycle between these extremes.

People who have these chronic fluctuations in mood do not know a healthy sense of wellbeing. Their emotional experiences negatively impact how they feel, their connections to school and work, friends and family, as well as their general physical health. These mood fluctuations stem from illness—specifically a mental illness—and are categorized as mood disorders.

Clinical Features of Mood Disorders

The predominant feature of a mood disorder is a chronic disturbance of mood that disrupts daily functioning. Sometimes called affective disorders, mood disorders are the most common mental illness, touching over a hundred million people worldwide.

Depressed mood is the most common symptom of the mood disorders and in its milder forms has been experienced by most people at some point.

Its experience is personal and is described in a variety of ways by different people:

  • sometimes as a profound lowering of spirits, subjectively different from normal unhappiness;
  • sometimes as an unpleasant absence of emotions or emotional range; and
  • sometimes as a more physical symptom of “weight” or “blackness” weighing down on the head or chest.

Increasingly, severe forms of depressed mood are indicated by:

  • the patient’s rating of greater severity as compared with previous experience,
  • increased pervasiveness of the low mood to all situations, and
  • decreased reactivity of mood (i.e. decreased ability of the mood to be lightened by pleasurable or encouraging events).

The two central clinical features of depressive illness are:

  1. pervasively depressed and unreactive mood and
  2. anhedonia—the loss of pleasure in previously pleasurable activities.

The clinical picture also includes the biological features of depression Opens in new window, thoughts of self-harm, and, in more severe cases, mood-congruent psychotic features.

The biological features include:

  • disturbance of sleep (particularly early morning waking and difficulty getting off to sleep),
  • reduced appetite, loss of libido, reduced energy levels, and subjective impression of poorer concentration and memory.

Many depressed patients will have thoughts of deliberate self-harm or ending their lives as a way of ending their suffering. With increasingly severe depressed mood there are increasingly frequent and formed plans of suicide. The development of a sense of hopelessness towards the future is a worrying sign.

Mania Opens in new window and depression Opens in new window are often thought of as two extremes of mental illness with normality or euthymia in the middle.

Morbid change in mood (either elevation or depression) can more accurately be considered as being on one side a coin with normality on the other. Some patients display both manic and depressive features in the one episode—a mixed affective state.

Manic and depressive illnesses have, in common, increased lability (i.e. susceptibility to change) of mood, increased irritability, decreased sleep, and an increase in subjective anxiety.

The core clinical features of manic illnesses are sustained and inappropriate elevation in mood (often described as feeling on top of the world) and a distorted or inflated estimate of one’s importance and abilities. With increasingly severe episodes of manic illness there is loss of judgment, an increase in inappropriate and risky behavior, and the development of mood-congruent delusions.

Etiology of Mood Disorders

The history of understanding mental illness started with the dawn of man, in the form of primitive beliefs in mysticism Opens in new window, mythology Opens in new window, and demonology Opens in new window. Individuals afflicted with depression Opens in new window, euphoria Opens in new window, or unusual behaviors were seen as evil or possessed.

Interventions were often cruel and barbaric at that time, including blistering, bloodletting, and the drilling of holes in the skull to exorcise evil spirits. Some remedies were more direct in the deadliness. Hanging, burning, and drowning were frequently used to “treat” mental illness.

As time moved forward and centuries passed, logic replaced archaic thinking, and science booted supernatural beliefs. Over the last fifty years, much of the scientific research on mental illness has been devoted to understanding the relationship between the brain and the body.

Though we’ve evolved from the antiquated views of disease, we carry with us some of the prehistoric ways of thinking. For example, Mania—the Greek Goddess of madness—is a word we still use today to clinically describe behavior.

Research has shown no singular causal root to explain mental illness. Instead, multi-determining factors explain why one person is more vulnerable to mental illness than is another. In this vein, contemporary clinicians use the whole-person approach called the Diathesis-Stress Model.

Diathesis-Stress Model

The Diathesis-Stress Model looks at the interactions that occur between a person’s biology, social environment, and unique temperament to explain the development of a mood disorder.

  1. Biology

For decades, evidenced-based data has shown that many mental illnesses stem from biological issues. Specifically, children and adults with mental illness have difficulties in the areas of neuro-transmission—the process by which neurons and the brain communicate.

These signaling networks can also show disruptions in the production and/or absorption of brain chemical messengers, called neurotransmitters.

Though there are hundreds of neurotransmitters that work in our body, serotonin, norepinephrine, dopamine, glutamate, and gamma-aminobutyric acid stand in the forefront when it comes to linking biology and mental illness.

Neuropeptides—protein-like molecules used by neurons to communicate with each other—like cholecystokinin and galanin have also been linked to mental illness. Other studies have shown structural differences in brain regions responsible for emotions, memory, motivation, and personality, like the hippocampus Opens in new window, amygdala Opens in new window, and prefrontal cortex Opens in new window.

Further investigations into the origin of mental illness illustrate discrepancies involving hormones and the related organs in the neuroendocrine system.

What we can glean from all this data is that mental illness has a neurobiological basis. Now, how does this happen? In a word, epigenome.

We’ve all heard the term DNA. Housed within your DNA Opens in new window is a genome, which holds the genetic code you inherit from your mother and your father, and the family lineage of your ancestors. This genetic code contains instructions for the unique building of your brain and body.

Within your genome Opens in new window is an epigenome—and your epigenome switches certain genes on or off. This turning on and off is called gene expression, and these gene expressions are involved in the biological basis for mental illness. Judith Horstman writes in the book The Scientific American Brave New Brain

“that the epigenome can be affected by many things, from aging and diet to environmental toxins to even what you think and feel.”

So, how you live your life, the stressors that fall on your shoulders, the experiences you move through, what you eat, drink, breathe, feel, and think affect your epigenomes and, thus gene expression Opens in new window.

So, it’s not nature or nurture, but nature and nurture. It’s also important to remember that mental disorders are not triggered by a single gene, but rather by varying gene expressions.

The science of who you are—your unique biology and biography—called epidemiology Opens in new window, explains why some of us have mental illness, while others do not.

  1. Social Environment

Genes Opens in new window, however, are not destiny. Your social environment plays a significant role in determining who you are. Sometimes, certain experiences trigger mental illness or contribute to its development in children and adults. These are called risk factors. Risk factors are not isolated events, but rather complex interactions that press on us.

So, what kinds of issues place you at risk for developing a mental illness?

National and global studies point to many of the same factors. These include variables that can be sudden (like a hospitalization or a death) or chronic (like poverty or physical abuse).

Risk factors also include your response style to life events.

  • Do you isolate yourself?
  • Does negative thinking keep you from seeing the positive?
  • Do you believe that you are helpless and powerless?

Identifying risk factors has a twofold gain. Research shows that mental disorders can be significantly reduced if at-risk children are identified early and receive supportive interventions.

For adults, recognizing risk factors can serve as a focal point as they start their recoveries. Here are some examples of risk factors:

Risk factors
Academic failureChild abuseAddiction
Chronic illnessCrimeParental illness
Cultural considerationsPeer rejectionDeath
DivorcePoor nutritionEmotional neglect
Exposure to toxinsPoor parentingPoverty
Poor prenatal/postnatal careIlliteracyPoor resiliency
Family discordSexual abuseStres
HospitalizationFinancial hardshipIsolation
TemperamentHomelessnessSeparation or loss
Learning problemsTerminal illnessViolence
Negative thinking stylesLow self-esteemWar
  1. Unique Temperament

Taking a look at my life history, the author recounted, shows many risk factors that made me vulnerable to depression.

As a baby and young child, my temperament was passive and quiet. I wasn’t demanding and didn’t protest when I was uncomfortable—or when things were stressful. Family discord and a series of losses and separations left me frightened and alone.

As I grew older, I experienced physical and sexual abuse, as well as learning problems and academic failure. I closed down, isolated myself, and descended into a pattern of negative thinking.

These experiences interlaced with the strong genetic line of depression from my family to create the perfect storm for mental illness. Tracing my biology and my biography helped me understand why I had a mood disorder.

Conceptual View of Mood Disorders

A good way to understand mood disorders is to view them in three clusters: unipolar (in which mood roots itself in a depressive state), bipolar (in which mood fluctuates between the lows of depression and highs of mania), and other (in which mood is affected by other disorders or conditions).

For reason of space, these varying mood disorders are are discussed in its designated literature here Opens in new window.

    The research data for this work heavily relied on:
  1. Living with Depression: Why Biology and Biography Matter along the Path to ... By Deborah Serani
  2. Oxford Handbook of Psychiatry By David Semple, Roger Smyth