Most people think of depression as a period of excessive sadness. While sadness is one symptom of major depressive disorder, it is only one of nine possible symptoms. The symptoms must:

• Be present for at least two weeks
• Represent a change from typical functioning
• Interfere with daily activities
• Occur most of the day, nearly every day

Major depressive disorder is not the only mental illness that includes depressive mood as its primary symptom. However, it is the one most commonly referred to as “depression.” There are ten distinct disorders collectively referred to as depressive disorders. Depressive mood is the one symptom they all have in common. Other physical, emotional, and cognitive symptoms may also be present.

When doctors and therapists evaluate a patient for a possible diagnosis, they are looking for at least five of the following symptoms:

• Depressive or irritable mood
• Anhedonia — the loss of pleasure or interest
• Unintentional changes in appetite or weight
• Insomnia or hypersomnia
• Psychomotor retardation or agitation
• Lethargy — fatigue or loss of energy
• Misplaced feelings of worthlessness or guilt
• Cognitive impairment — the inability to focus, concentrate, or make decisions
• Suicidal ideation — recurrent thoughts of death, self-harm, or suicidal behaviors

In the coming weeks, we will explore each of these symptoms in detail. Our focus will be on the neurobiological aspects of major depressive disorder. We’ll discuss the neurological link between emotional and physical pain and examine the role of neurotransmitters. We’ll also take a closer look at the human body’s ability to restore healthy neurological functioning, looking at non-pharmacological ways to counteract the symptoms of major depressive disorder.

There are many myths about major depressive disorder. As we explore each symptom, we will also examine some common misconceptions about each symptom and their assumed causes. We will challenge such ideas as:

• Situational depression isn’t really depression
• You need a good reason to be depressed
• Antidepressants are sufficient to resolve depression
• Family dysfunction causes depression
• Depression is a sign of emotional weakness
• Just think happy thoughts

See more helpful articles:

16 Things to Know About Depression

10 Signs It’s Time to Get Help for Depression

Top 10 Depression Myths Explored