Depression: Symptoms and Diagnosis

Symptoms of depression

The criteria used to make a diagnosis of depression are based on the symptoms that are present, so the list of possible symptoms is similar:3,5,10

• Depressed mood - feeling sad or low
• Reduced interest or pleasure in activities previously enjoyed, loss of sexual desire
• Unintentional weight loss (without dieting) or low appetite
• Insomnia (difficulty sleeping) or hypersomnia (excessive sleeping)
• Psychomotor agitation (for example, restlessness, pacing up and down), or psychomotor retardation (slowed movements and speech)
• Fatigue or loss of energy
• Feelings of worthlessness or guilt
• Worsened ability to think, concentrate or make decisions
• Recurrent thoughts of death or suicide, or attempt at suicide.

Signs are the features that may be noticed by the doctor and others - as opposed to the symptoms that patients can describe themselves. Signs of a person with depression include:5

• Appearing miserable, tearful eyes, furrowed brows, down-turned corners of the mouth
• Slumped posture, lack of eye contact and facial expression
• Little body movement, and speech changes (for example, soft voice, use of monosyllabic words)
• Gloomy, pessimistic, humorless, passive, lethargic, introverted, hypercritical of self and others, complaining.

The YouTube video below is produced by the National Alliance on Mental Illness - it gives a picture of the features of depression.

Tests and diagnosis of depression

Diagnosis of depression starts with a consultation with a general practitioner or mental health specialist (psychologist or psychiatrist).3

It is important to seek the help of a health professional to rule out different causes of depression, ensure an accurate differential diagnosis, and secure safe and effective treatment.

As for most visits to the doctor, there may be a physical examination to check for physical causes and coexisting conditions. Questions will also be asked - "taking a history" - to establish the symptoms, their time course, and so on.

For depression, a number of structured interviews have been designed to ask questions that are sensitive toward making the diagnosis. These range from one questionnaire that involves just two questions to test for the two "core" symptoms of depression:3

• Over the past month, have you often been bothered by feeling down, depressed or hopeless?
• Do you have little interest or pleasure in doing things?

Doctors may also follow the criteria set out by the Diagnostic and Statistical Manual of Mental Disorders (DSM-5).4

Here, depression is diagnosed if five or more criteria are met, from a list of nine, and represent a change from normal and have been present for the past two weeks.11

At least one of the symptoms must be one of the two above - that is, either depressed mood or loss of interest or pleasure. The full list of criteria are:3,11

Low mood for most of the day every day is one of the flags for depression.

• Depressed mood most of the day, nearly every day
• Noticeably reduced interest or pleasure in all, or almost all, activities most of the day, nearly every day
• Significant unintentional weight loss or low appetite nearly every day
• Insomnia or hypersomnia nearly every day
• Psychomotor agitation (for example, restlessness, pacing up and down), or psychomotor retardation (depressed body movements, speech, reaction times) nearly every day
• Fatigue or loss of energy nearly every day
• Feelings of worthlessness or guilt nearly every day
• Worsened ability to think or concentrate, or indecisiveness, nearly every day
• Recurrent thoughts of death or suicide, or attempt at suicide.

The five or more symptoms must be severe enough to affect daily activities or social interactions, or cause significant distress. It must not be possible to explain them by another medical condition, substance use or other causes.3,11

For example, dementia may present as depression, and vice versa. However, memory testing can distinguish the two, so people being investigated for depression may be asked to answer questions that test their cognitive abilities.3

Other underlying causes of depression that should be diagnosed and treated include:3,5

• Carbon monoxide poisoning
• Substance misuse (alcohol, anabolic steroids, cannabis, cocaine, narcotics)
• Prescription drug side-effects
• Hypothyroidism
• Brain tumor
• Parkinson's disease
• Vitamin deficiency.

Questionnaires help to diagnose depression and its severity.

Some questionnaires help doctors to assess the severity of depression. The Hamilton depression rating scale, for example, has 21 questions, with resulting scores picking up normal (a score of 7 or below) and mild or moderate depression, to severe or very severe.8

The Hamilton scale is the most widely used assessment instrument in the world for clinicians rating depression.8

A similar questionnaire is available online for patients to rate their own depression and severity as an indication of whether they should see a doctor or therapist - it does not provide a definitive diagnosis but can be used to "start a conversation" with a doctor.12

The depression screening tool provided by Mental Health America is interactive and returns an indication once all the questions are answered. Submitting other demographic details is optional, purely for the non-profit's research purposes.

Depression or grief? Differential diagnosis

Major depression and grief over the death of a loved one share common symptoms but it is possible to distinguish a grief reaction from depression.

For example, suicidal thoughts or profound and inappropriate guilt are rare with normal bereavement, and self-esteem tends to be maintained.3,10

Other distinguishing features may be that grief comes in waves, whereas depression is constant and unremitting. Or the person suffering a bereavement is able to look forward to the future, whereas a depressed person has no positive feelings for the future.