Early childhood trauma.

Some events affect the way your body reacts to fear and stressful situations.

Brain structure.

There’s a greater risk for depression if the frontal lobe of your brain is less active.

Drug use.

A history of drug or alcohol misuse can affect your risk.

Medical conditions.

Certain conditions, such as chronic illness, insomnia, or chronic pain, may put you at higher risk.

Family history.

You’re at a higher risk for developing depression if you have a family history of depression or another mood disorder.

Major Depressive Disorder

The person is in a depressed mood most of the day, nearly every day, for two weeks or more; loss of interest in most or all activities, significant weight loss or weight gain or change in appetite, insomnia or sleeping more than usual, fatigue, feelings of worthlessness, difficulty concentrating, or thoughts of death.

Substance/medication-induced depressive disorder

This disorder is characterised by a prominent and persistent change in mood, or a marked decrease in interest or pleasure in daily activities and hobbies. These symptoms occur as a result of the patient consuming a substance (i.e. illegal drugs, toxins, other medications, etc.)

Premenstrual Dysphoric Disorder

Premenstrual dysphoric disorder (PMDD) is a very severe form of premenstrual syndrome (PMS). It is a condition in which a woman has severe depression symptoms, irritability, and tension before menstruation. Physical or emotional symptoms most often occur about 5 to 11 days before a woman starts her monthly menstrual cycle.

Dysthymia

Also called Persistent Depressive Disorder, a continuous long-term form of depression. It is not as severe as major depression, but the person may still lose interest in normal daily activities, feel hopeless, lack productivity, have low self-esteem and an overall feeling of inadequacy.

A person with dysthymia is sometimes described as having a gloomy personality, constantly complaining or incapable of having fun.

Disruptive Mood Dysregulation Disorder

DMDD is characterised by severe and recurrent temper outbursts that are grossly out of proportion in intensity or duration to the situation. These occur, on average, three or more times each week for one year or more. Between outbursts, children with DMDD display a persistently irritable or angry mood, most of the day and nearly every day, that is observable at home and in the classroom.

Depressive Disorder Due to another medical condition

Certain medical conditions can lead to a state of depression in an individual. For example, hypothyroidism – which can result in weight gain – can induce clinical and psychiatric depression. Some other conditions that may cause depression are heart disease, a stroke, Parkinson’s disease, hormone problems, and cancer.