Depression is a state of low mood and aversion to activity. It can affect a person’s thoughts, behavior, motivation, feelings, and sense of well-being. It may feature sadness, difficulty in thinking and concentration and a significant increase or decrease in appetite and time spent sleeping. People experiencing depression may have feelings of dejection, hopelessness and, sometimes, suicidal thoughts. It can either be short term or long term. The core symptom of depression is said to be anhedonia, which refers to loss of interest or a loss of feeling of pleasure in certain activities that usually bring joy to people. Depressed mood is a symptom of some mood disorders such as major depressive disorder or dysthymia; it is a normal temporary reaction to life events, such as the loss of a loved one; and it is also a symptom of some physical diseases and a side effect of some drugs and medical treatments.

Life events

Adversity in childhood, such as bereavement, neglect, mental abuse, physical abuse, sexual abuse, or unequal parental treatment of siblings can contribute to depression in adulthood. Childhood physical or sexual abuse in particular significantly correlates with the likelihood of experiencing depression over the victim’s lifetime.

Life events and changes that may influence depressed moods include (but are not limited to): childbirth, menopause, financial difficulties, unemployment, stress (such as from work, education, family, living conditions etc.), a medical diagnosis (cancer, HIV, etc.), bullying, loss of a loved one, natural disasters, social isolation, rape, relationship troubles, jealousy, separation, or catastrophic injury. Adolescents may be especially prone to experiencing a depressed mood following social rejection, peer pressure, or bullying.

Personality

Changes in personality or in one’s social environment can affect levels of depression. High scores on the personality domain neuroticism make the development of depressive symptoms as well as all kinds of depression diagnoses more likely, and depression is associated with low extraversion. Other personality indicators could be: temporary but rapid mood changes, short term hopelessness, loss of interest in activities that used to be of a part of one’s life, sleep disruption, withdrawal from previous social life, appetite changes, and difficulty concentrating.

Medical treatments

Depression may also be the result of healthcare, such as with medication induced depression. Therapies associated with depression include interferon therapy, beta-blockers, isotretinoin, contraceptives, cardiac agents, anticonvulsants, antimigraine drugs, antipsychotics, and hormonal agents such as gonadotropin-releasing hormone agonist.

Substance-induced

Several drugs of abuse can cause or exacerbate depression, whether in intoxication, withdrawal, and from chronic use. These include alcohol, sedatives (including prescription benzodiazepines), opioids (including prescription pain killers and illicit drugs such as heroin), stimulants (such as cocaine and amphetamines), hallucinogens, and inhalants.

Non-psychiatric illnesses

Depressed mood can be the result of a number of infectious diseases, nutritional deficiencies, neurological conditions, and physiological problems, including hypoandrogenism (in men), Addison’s disease, Cushing’s syndrome, hypothyroidism, hyperparathyroidism, Lyme disease, multiple sclerosis, Parkinson’s disease, chronic pain, stroke,^[18] diabetes, and cancer.

Historical legacy

Researchers have begun to conceptualize ways in which the historical legacies of racism and colonialism may create depressive conditions.

Measures

Measures of depression as an emotional disorder include, but are not limited to: Beck Depression Inventory-11 and the 9-item depression scale in the Patient Health Questionnaire. Both of these measures are psychological tests that ask personal questions of the participant, and have mostly been used to measure the severity of depression. The Beck Depression Inventory (BDI) is a self-report scale that helps a therapist identify the patterns of depression symptoms and monitor recovery. The responses on this scale can be discussed in therapy to devise interventions for the most distressing symptoms of depression. Several studies, however, have used these measures to also determine healthy individuals who are not suffering from depression as a mental disorder, but as an occasional mood disorder. This is substantiated by the fact that depression as an emotional disorder displays similar symptoms to minimal depression and low levels of mental disorders such as major depressive disorder; therefore, researchers were able to use the same measure interchangeably. In terms of the scale, participants scoring between 0-13 and 0-4 respectively were considered healthy individuals.

Another measure of depressed mood would be the IWP Multi-affect Indicator. It is a psychological test that indicates various emotions, such as enthusiasm and depression, and asks for the degree of the emotions that the participants have felt in the past week. There are studies that have used lesser items from the IWP Multi-affect Indicator which was then scaled down to daily levels to measure the daily levels of depression as an emotional disorder.

Connections

Alcoholism

Alcohol can be a depressant which slows down some regions of the brain, like the prefrontal and temporal cortex, negatively affecting our rationality and memory. It also lowers the level of serotonin in our brain, which could potentially lead to higher chances of a depressive mood.

The connection between the amount of alcohol intake, level of depressed mood, and how it affects the risks of experiencing consequences from alcoholism, were studied in a research done on college students. The study used 4 latent, distinct profiles of different alcohol intake and level of depression; Mild or Moderate Depression, and Heavy or Severe Drinkers. Other indicators consisting of social factors and individual behaviors were also taken into consideration in the research. Results showed that the level of depression as an emotion negatively affected the amount of risky behavior and consequence from drinking, while having an inverse relationship with protective behavioral strategies, which are behavioral actions taken by oneself for protection from the relative harm of alcohol intake. Having an elevated level of depressed mood does therefore lead to greater consequences from drinking.

Bullying

Social abuse, such as bullying, are defined as actions of singling out and causing harm on vulnerable individuals. In order to capture a day-to-day observation of the relationship between the damaging effects of social abuse, the victim’s mental health and depressive mood, a study was conducted on whether individuals would have a higher level of depressed mood when exposed to daily acts of negative behavior. The result concluded that being exposed daily to abusive behaviors such as bullying has a positive relationship to depressed mood on the same day.

The study has also gone beyond to compare the level of depressive mood between the victims and non-victims of the daily bullying. Although victims were predicted to have a higher level of depressive mood, the results have shown otherwise that exposure to negative acts has led to similar levels of depressive mood, regardless of the victim status. The results therefore have concluded that bystanders and non-victims feel as equally depressed as the victim when being exposed to acts such as social abuse.

Creative thinking

Divergent thinking is defined as a thought process that generates creativity in ideas by exploring many possible solutions. Having a depressed mood will significantly reduce the possibility of divergent thinking, as it reduces the fluency, variety and the extent of originality of the possible ideas generated.

However, some depressive mood disorders might have an positive effect for creativity. Upon identifying several studies and analyzing data involving individuals with high levels of creativity, Christa Taylor was able to conclude that there is a clear positive relationship between creativity and depressive mood. A possible reason is that having a low mood could lead to new ways of perceiving and learning from the world, but it is unable to account for certain depressive disorders. The direct relationship between creativity and depression remains unclear, but the research conducted on this correlation has shed light that individuals who are struggling with a depressive disorder may be having even higher levels of creativity than a control group, and would be a close topic to monitor depending on the future trends of how creativity will be perceived and demanded.

Stress management techniques

There are empirical evidences of a connection between the type of stress management techniques and the level of daily depressive mood.

Problem-focused coping leads to lower level of depression. Focusing on the problem allows for the subjects to view the situation in an objective way, evaluating the severity of the threat in an unbiased way, thus it lowers the probability of having depressive responses. On the other hand, emotion-focused coping promotes a depressed mood in stressful situations. The person has been contaminated with too much irrelevant information and loses focus on the options for resolving the problem. They fail to consider the potential consequences and choose the option that minimizes stress and maximizes well-being.