Depression is marked by profound melancholy, thoughts of futility and worthlessness, and separation from others. Depressive symptoms are classified into four major groups:

• Affective symptoms: sadness, dejection, worthlessness, apathy, anxiety, crying, and brooding
• Cognitive symptoms: guilt, pessimism, loss of interest and motivation, negative thinking, suicidal thoughts, and inability to concentrate
• Behavioural symptoms: anhedonia, decreased productivity, low energy, agitation, neglect of personal appearance, psychomotor retardation, and social withdrawal
• Physiological symptoms: loss of appetite or increase in appetite, weight gain or weight loss, sleep disturbances, and loss of sex drive

Depression is more prevalent in young adults (18-29 years old) than in adults over the age of 60. Although more women attempt suicide, men take their lives in greater numbers.

Types of Depression

The DSM-V divides depressive disorders into four categories:

Major Depressive Disorder

Also known as clinical depression, it is a mental condition defined by a consistently sad mood and a long-term loss of joy or interest in life, along with accompanying symptoms such as disrupted sleep, feelings of guilt or inadequacy, and suicidal thoughts. It affects roughly 20% of women and 12% of men worldwide. The symptoms are usually severe but short-lived. The symptoms must last for two weeks and show a change from one’s level of functioning.

Dysthymia (Persistent Depressive Disorder)

This is a milder but chronic form of depression that lasts for a long time. The person may lose interest in typical day-to-day activities, feel hopeless, have low self-esteem, and have a general sense of inadequacy and be unproductive.

Disruptive Mood Dysregulation Disorder

This is a childhood condition characterized by severe irritation, wrath, and frequent rage outbursts or tantrums resulting in trouble functioning in more than one setting.

Premenstrual Dysphoric Disorder (PMDD)

A severe form of premenstrual syndrome characterized by physical and behavioural symptoms that typically improve when the menstrual cycle starts. It creates severe mood swings, which can disrupt work and jeopardize relationships.

Depression in Children

Children can also develop depression, and symptoms differ from typical behaviours observed. When a child's sadness persists and interferes with his or her everyday social activities, interests, academics, or family life, he or she may be diagnosed with a depressive illness. Symptoms include:

• Sadness
• Withdrawal
• Feelings of hopelessness
• Decreased thinking
• Mood shifts
• Clinginess
• Impatience
• Hypersensitivity
• Reactiveness

Causes of Depression in Children

Depression in children can be caused by:

• Genetics: A child with depression may inherit depressive genes from parents.
• Neurotransmitters: Children with lower serotonin, norepinephrine, and dopamine levels are more prone to depression.
• Environmental factors: Difficulties at school, with peers, and within the family can result in extreme unhappiness, withdrawal, and anger toward others. Stressors, unstable households, and parent-child socialization patterns can all contribute to depression.
• Cognitive factors: Negative thinking patterns can significantly increase a child's chances of developing depression, as they interpret their world, future, and themselves in a negative, gloomy context.