This is the first in a series of articles about depression.

Q: What is Major Depressive Disorder?

A: According to the American Psychiatric Association diagnostic criteria for Major Depressive Disorder, a person must experience five or more of the symptoms continuously for at least two weeks in order to meet the criteria. In addition, two of those symptoms must include low mood or persistent sadness and a marked loss of interest or pleasure in activities normally enjoyed. The other symptoms of MDD include:

• Change in appetite or weight (either increase or decrease),

• Change in activity: psychomotor agitation. (More active than usual) or psychomotor retardation (less active than usual),

• Insomnia (difficulty sleeping) or sleeping too much,

• Feeling tired or not having any energy,

• Feelings of guilt or worthlessness,

• Difficulties concentrating and paying attention,

• Thoughts of death or suicide.

There are co-occurring conditions with which people commonly also have depression. Those persons with anxiety, panic disorder, and personality disorders frequently develop depression. The depression should be treated first. Anxiety frequently improves following the treatment for depression.

Eating disorders such as anorexia and bulimia might co-occur with depression. With eating disorders, they are usually the main target for treatment rather than the depression. Co-occurring disorders also include obsessive-compulsive disorder and phobias.

Additional co-occurring conditions include post-traumatic stress disorder and attention-deficit hyperactivity disorder. Treating depression successfully usually improves co-occurring disorders. Conversely, successful treatment of PTSD, ADHD, or substance abuse usually improves depression.

Other behaviors and conditions frequently co-existing with depression are smoking, obesity and physical inactivity, sleep disturbances, and epilepsy. Children with high levels of anxiety can be higher risks for depression as adults.

Depression can occur with other major medical illnesses such as cancer, diabetes, heart disease, and Parkinson’s disease. Depression can worsen these problems and they can worsen depression. Sometimes medications for these illnesses cause side effects that worsen depression.

Scientists can pinpoint factors that can trigger depression such as bereavement, illnesses, chronic pain, cancer, social isolation, loneliness, and stresses such as divorce or money problems. Scientists are unclear about why some people get depressed and others don’t.

However, scientists can identify the factors most likely to cause depression in adults. First is genetics, when mood disorders and suicide run in families; then there is brain structure and chemistry. Other causative factors include trauma or abuse at an early age that can cause long-term changes in how the brain handles stress and fear. Substance abuse is a factor causing depression, as are hormonal changes in women in pregnancy, thyroid problems, or menopause.

Then there are risk factors that make people vulnerable to depression, in addition to the ones already reiterated as conditions commonly associated with depression. Others include lack of social support, recent stressful life experiences, unemployment or underemployment, and health problems or severe chronic pain.

If a person is depressed about a situation that can be changed, changing the situation usually alleviates the depression. Examples would include finding a new job, moving, consulting a credit advisor about resolving money issues.

Symptoms of depression vary by gender and age. Men are less apt to acknowledge feelings of self-hate and hopelessness. Instead, they tend to complain about fatigue, irritability, sleep problems, and loss of interest in hobbies and work. Men are more likely to experience behaviors such as anger, aggression substance abuse, and reckless behavior.

Women, on the other hand, are more likely to experience feelings of guilt, overeating, sleeping too much, and weight gain. In women, depression is impacted by hormonal influences during menstruation, pregnancy and menopause. One in seven women experiences Postpartum Depression, a condition that follows childbirth.

Symptoms of depression in teens are often irritability, agitation, and anger, not sadness. Teens may also experience headaches, stomachaches or other physical complaints. In older adults, the majority of complaints are about physical symptoms of depression, such as fatigue, unexplained aches and pains, pain, memory problems. Older adults can start neglecting their personal appearance and stop taking their medication, serious signs of self-neglect. But depression is not a normal part of aging.

Additional groups of people who are higher risk for depression are lesbian, gay, bisexual, transgender and questioning people. They face discrimination from society, and sometimes from family, co-workers or classmates. These conditions frequently make this group vulnerable to mental health problems like depression.

Regarding children and teens, those at higher risk for depression include youth with ADHD, learning disorders, anxiety disorders, and oppositional defiance disorders. Also at increased risk for depression are children who experienced stress or trauma, a serious loss or have a family history of depression. Children express depression as aches and pains. Depressed teens engage in risky behavior such as abusing alcohol or illegal drugs, having poor school performance, or running away.

Major Depressive Disorder is by far the most prevalent type of depression. The second most prevalent type of depression is persistent depressive disorder. This type has symptoms that are less severe than major depression but this type lasts two years. It is called Dysthemia.

Next week’s article will continue with types of depression.

Judy Caprez is professor emeritus at Fort Hays State University.