A Look at Major Depressive Disorder


Major Depressive Disorder (MDD) is a mental health condition characterized by symptoms such as fatigue, feelings of worthlessness, insomnia, diminished interest or pleasure in nearly all daily activities, and a depressed mood.

What Are the Causes of Major Depressive Disorder?

  • Biological factors – Neurotransmitters (serotonin, norepinephrine, and dopamine) and hormones (cortisol, thyroid hormones, and growth hormones) as well as the limbic system, the basal ganglia, and the hypothalamus
  • Genetic factors
  • Psychosocial factors

Who’s Most at Risk?

Woman having a conversation with her therapist on couch in office

  • Occurs in 10%-25% of women and 5%-12% of men
  • Tends to develop in adulthood, with a mean onset age of 40 years old, but can start in childhood and persist into adulthood
  • Occurs more frequently in divorced or separated individuals

Currently, there is no clear association with socioeconomic status and MDD.

What Symptoms Should I Look Out For?

  • Depressed mood nearly every day for at least two weeks
  • Changes in mood NOT caused by substance abuse or things like bereavement, financial ruin, serious medical illness, or disability
  • Impairment of functioning
  • Tearfulness
  • Feelings of worthlessness, hopelessness, emptiness, and helplessness

To remember other common symptoms of MDD, use the mnemonic device SIGECAPS.

Sleep – Does the individual have problems with either significantly increased or decreased sleep?

Interest – Does the individual have decreased interest in pleasurable activities, also known as anhedonia?

Guilt – Is the individual experiencing feelings of guilt?

Energy – Is the individual experiencing decreased energy?

Concentration – Does the individual have decreased concentration?

Appetite – Does the individual have an increased or decreased appetite? Have they experienced extreme weight loss (i.e., a change of more than 5% in one month)?

Psychomotor agitation or retardation – Is the individual experiencing observable restlessness or slowing down?

Suicidality – Is the individual having thoughts of suicide or have they attempted suicide?

Mature Lady doctor advises the patientAnswering yes to one of these indicators may not mean that the individual is experiencing MDD; however, even demonstrating one symptom can be cause for concern. By reaching out and expressing support, you may encourage the individual to get the help that they need.

Getting Help

The Light Program provides intensive outpatient mental health treatment that can help those suffering from depression, thoughts of suicide, and anxiety. If you think The Light Program may be right for you or a loved one, call 1-888-686-7511 or fill out a contact form so we can get in touch with you as soon as possible.

This information is not a substitute for an evaluation by a licensed professional.


  1. Kaplan and Sadock’s Synopsis of Psychiatry, ninth edition.
  2. Diagnostic and Statistical Manual of Mental Disorders, fifth edition.

Contributed by Nito Gan, M.D.