Depression is a global health burden and continues to increase with each passing day. As per the WHO, globally, more than 264 million people of all ages suffer from depression. It is one of the leading causes of disability as measured by Years Lived with Disability (YLDs) and the fourth leading contributor to disease’. Besides physical and mental illness, depression is also directly linked with suicides risk or suicidal behaviour. The increasing prevalence of depression is likely to continue in the coming years due to various factors such as stigma, lack of awareness, limited treatment availability and lack of trained health-care providers and resources.

What is depression?

Depression is a mental disorder that negatively affects the thinking and the feeling of the person. The impact of depression can be observed on the person’s behaviour. It results in the loss of interest in activities that the person once enjoyed doing or performing. Physically it leads to a lack of concentration in the work or study, which ultimately results in productivity loss. Depression encompasses a large number of symptoms ranging from mild to severe form.

What are the primary signs and symptoms of depression?

The signs and symptoms of depression vary from person to person and also with time. In some cases, only a few symptoms may occur, while in some cases, the affected person may experience several symptoms. The common symptoms associated with depression include irritability, anxiety, appetite changes, fatigue, helplessness, and restlessness. Along with these in some cases, the person may experience difficulty in remembering, or making decisions, feelings of worthlessness and a disturbance in sleep patterns. 

How does depression affect a person?

Depression is a mental illness that affects not only the mental but the physical health of a person as well. The affected person might experience a change in the cardiovascular, digestive and immune systems, which in turn affects workplace productivity and concentration. Similarly, the chances for self-harm (or suicide) and hurting another person also increases. Weight loss, trouble in sleeping, chronic pain, and inflammation are some of the complications that may develop as the depression progresses.

Are there any risk factors for depression?

Depression is prevalent across all age groups, sex, race and geographies. Various social, psychological, environmental and biological factors lead to the development of depression. Family history is one factor that may contribute to the development of depression; however, the exact cause remains unclear. Similarly, the trauma or stress due to conflict or civil war, physical or emotional abuse, significant changes in life, chronic illness, poor nutrition, dependence on medications, substance abuse, sudden unexpected events in life can lead to depression. In recent times social media has also emerged as a critical factor. In adults, unemployment is one of the significant factors for depression. 

What are the major types of depression?

According to the range of conditions, severity and the types of symptoms, depression is classified as:

Major Depressive Disorder (MDD) – Major depressive disorder (MDD) is also referred to as clinical depression, classic depression and unipolar depression. MDD leads to severe medical illness that can affect mood, behaviour, thought process, interpersonal relationships, and other daily activities. The person with MDD might experience the symptoms throughout the day or even every day. The symptoms may last for a week or months.

According to the Anxiety & Depression Association of America, in 2017, around 17.3 million aged 18 years or older in the U.S. had experienced at least one major depressive episode in the last year, representing 6.7% of all American adults. While the major depressive disorder can develop at any age, the median age at onset is 32.5 years old.

To address Major Depressive Disorder and to provide an effective therapeutic option, companies such as Axsome Therapeutics, SAGE Therapeutics, Janssen Pharmaceutica, Minerva Neurosciences, Relmada Therapeutics, Intra-Cellular Therapies, among several others, are involved in developing therapies.

Manic depression – Manic depression is also known as bipolar disorder. In Manic Depression, the person might experience alternate episodes of depression and happiness. The affected person during the depression phase finds it challenging to concentrate on work, feel low energy, sadness, and loss of interest in activities. While at the manic phase, the person feels high energy, increased self-esteem, creativity, confidence, racing thoughts and many other symptoms. 

As per the DelveInsight, the total diagnosed prevalent population of Bipolar Depression in the 7MM was 1,857,545 in 2017. The estimates show the highest diagnosed prevalence of Bipolar Depression in the United States, with 740,715 cases in 2017. Based on the severity of Bipolar Depression, total diagnosed prevalent cases of Manic Depression are categorised into mild, moderate and severe. In the 7MM, the number of patients experiencing depressive episodes is higher in BD-II than in BD-I.

The Manic Depression treatment aims to achieve a high level of psychosocial function and health-related quality of life. Being a highly recurrent disorder, sometimes medication needs to continue even if the patient feels well. Worldwide, some of the key companies are diligently working toward developing novel treatment therapies for Manic Depression with a considerable amount of success over the years. At present key players, such as Celon Pharma, Otsuka Pharmaceutical, NeuroRx, etc., are working in the therapeutics development for Bipolar Depression.

Postpartum Depression – Postpartum Depression also known as Perinatal Depression, has its onset during pregnancy or following the child’s birth. According to the American College of Obstetricians and Gynecologists, It is estimated that 14–23% of pregnant women experience depression during pregnancy, and 5–25% experience depression Postpartum. The hormonal changes that occur during pregnancy and childbirth trigger the changes in the brain that lead to mood swings. The person experiences extreme mood swings, loss of interest, appetite changes, baby‘s health and safety concerns, sadness, anxiety, social withdrawal, anger, exhaustion and many other symptoms. 

As per Delveinsight, the total diagnosed prevalent population of Postpartum Depression in the seven major markets was found to be 1,134,800 in 2017. In the EU5 countries, the diagnosed prevalence of Postpartum Depression was maximum in France with 98,040 cases, followed by the United Kingdom with 97,750 cases in 2017. At the same time, the least number of cases were found in Spain, i.e., 56,375 in 2017.

Some of the effective treatment options for PPD include antidepressant medications, cognitive-behavioural therapy (CBT), and interpersonal therapy. Apart from these, some other treatment options such as psychodynamic therapy, light therapy, exercise, and yoga are also available, but the current research evidence about the efficacy of such treatment regimens is more preliminary. Sage Therapeutics and Marinus Pharmaceuticals, Inc. are the two key players developing therapies for managing Postpartum Depression.

Persistent Depressive Disorder (PDD) – Persistent Depressive Disorder (PDD) is also known as a dysthymic disorder or dysthymia. PDD is a chronic depression that can last for at least two years. It is found to be more common in women and begin in childhood or in adulthood. The PDD is marked with a low and sad mood for most days or even for days. The exact cause of PDD is unknown. Lack of concentration, low self-esteem and energy, poor appetite or overeating, fatigue are some of the most common PDD symptoms. At present, antidepressant medicine is available in the market that can relieve PDD. It takes time to assess the impact of antidepressants on the patient. In case the person feels better, the prescription is required to take for several years. The sudden discontinuation of medication can affect the person. 

Similarly, Premenstrual Dysphoric Disorder (PMDD), Seasonal Affective Disorder (SAD), Atypical Depression are some other most common depression. 

Depression can have severe health complications or impairment if it remains untreated for a longer time. It becomes essential to pay attention to early signs and symptoms and consult a doctor in due time. Medications are available in the market to relieve the symptoms of depression. Similarly, at present several companies worldwide are exploring potential therapies for depression. Along with medications, talk therapy, counselling, or lifestyle changes can also minimise the symptoms. Numerous researches are going on to study depression, its diagnosis, and treatment options. Similarly, world health bodies such as WHO, through its mental health Gap Action Programme (mhGAP), monitor and help counties fight mental and neurological diseases. In the coming years, the launch of innovative treatments, increased investments in R&D, and rising awareness are expected to improve the situation for the people affected with depression and their families.