Mood disorders: types, symptoms, causes and treatment

"Mood disorder" is an umbrella term for mental health conditions in which mood is the main problem. Mood is more than a passing feeling. The NHS says depression is more than simply feeling unhappy or fed up for a few days: most people go through periods of feeling down, but when you are depressed you feel persistently sad for weeks or months. It adds that depression is a real illness with real symptoms, not a sign of weakness or something you can "snap out of".

In bipolar disorder the NHS describes extreme changes to mood, sometimes high (mania or hypomania) and sometimes low (depression), usually lasting a few days or weeks at a time, with stable periods in between that can last weeks, months or years.

Depression: the NHS lists psychological symptoms such as continuous low mood or sadness, feeling hopeless and helpless, low self-esteem, tearfulness, guilt, irritability, no motivation or interest, difficulty making decisions, and thoughts of suicide or self-harm. Physical symptoms include moving or speaking more slowly, changes in appetite or weight, constipation, unexplained aches and pains, lack of energy, low sex drive and disturbed sleep. Social symptoms include avoiding friends and neglecting hobbies. The NHS notes you are unlikely to have all of them, and that symptoms persist for weeks or months and interfere with work, social life and family life.

Bipolar disorder: the NHS describes high moods as feeling very happy and excited, very irritable, having a lot of energy and not needing much sleep, racing thoughts, talking fast, a high sex drive, feeling overly confident, being impulsive or extravagant, and in some cases hearing things that are not real or believing things that are not true. Low moods resemble depression.

Seasonal affective disorder: the NHS lists low mood, lack of interest in things you usually enjoy, feeling guilty, hopeless or worthless, restlessness, difficulty concentrating, eating and sleeping more than usual, and thoughts of suicide or self-harm, in a pattern that comes in winter and goes in summer. Cyclothymia causes periods of feeling low followed by periods of feeling very happy and excited when you do not need much sleep, are more sociable and impulsive and feel you have a lot of energy.

• Depression: low mood, hopelessness, loss of interest, tiredness, sleep and appetite changes.

• Mania or hypomania: elevated mood, reduced need for sleep, racing thoughts, impulsive behaviour.

• SAD: depression that follows the seasons, usually winter.

• Cyclothymia: frequent milder highs and lows without full depression or mania.

Depression: the NHS says treatment usually involves a combination of self-help, talking therapies and medicines, according to severity. For mild depression a GP may suggest watchful waiting (seeing you again after 2 to 4 weeks), guided self-help (usually 6 to 8 sessions based on cognitive behavioural therapy), exercise and talking therapy. For moderate to severe depression, a combination of an antidepressant and talking therapy such as CBT is often recommended and usually works better than either alone. People with severe depression may be referred to a specialist mental health team.

The NHS says CBT sessions are usually weekly or fortnightly for between 8 and 16 sessions depending on severity, and describes other options including interpersonal therapy, behavioural activation, problem-solving and psychodynamic psychotherapy.

Bipolar disorder: the NHS says it cannot be cured but treatment can help manage it, using medicines to help stabilise moods and talking therapy such as CBT. Some medicines need to be taken all the time, others only when symptoms get worse, and you should not stop bipolar medicine unless a doctor tells you to, even if you feel better. Some medicines are not safe in pregnancy, so talk to your doctor if you are pregnant or planning a pregnancy.

Seasonal affective disorder: the NHS lists antidepressants, talking therapies and light therapy, and says many people need treatment every winter. Light therapy is not usually available on the NHS because there is not enough evidence to tell whether it is effective. Cyclothymia: treatment usually involves talking therapy and sometimes medicines, aiming to stop it developing into full bipolar disorder, reduce symptoms and stop them coming back.

There is rarely a single cause. For depression, the NHS says there is sometimes a trigger, such as bereavement, losing a job or giving birth; people with a family history of depression are more likely to experience it, and you can also become depressed for no obvious reason.

For bipolar disorder, the NHS says it is not known exactly what causes it. You are more likely to have it if a parent, brother or sister has it, and factors that can increase the chance include childhood trauma or abuse, stressful events, recreational drugs such as cannabis or cocaine, and a parasite called Toxoplasma gondii. For SAD, it is not known exactly, but it is thought to be linked to reduced daylight in winter, which may change brain chemicals such as melatonin and serotonin.

The NHS says it is important to see a GP if you think you may be depressed, because many people wait a long time before seeking help and the sooner you see a doctor, the sooner you can be on the way to recovery. It gives a specific threshold: see a GP if you have symptoms of depression for most of the day, every day, for more than 2 weeks. For bipolar disorder it says to see a GP if you have extreme changes in mood that last a long time or affect everyday life, or if you have been diagnosed and treatments are not helping. If you are worried about someone else, encourage them to speak to their GP.

The NHS mental health pages carry a prominent notice that support is available if you or someone you know is having a mental health crisis or emergency, and point to its page on where to get urgent help for mental health. The NHS bipolar page says that if doctors are worried you are at risk of self-harm, suicide or harming someone else, you may need to stay in hospital or have support from a crisis team at home. If you are in immediate danger, call 999; for urgent but non-emergency advice, NHS 111 online has a mental health symptom checker.

• Routine GP appointment: low mood most of the day, every day, for more than 2 weeks.

• GP appointment: extreme mood changes that last a long time or affect daily life.

• Urgent help: thoughts of suicide or harming yourself or someone else, or a mental health crisis (NHS 111 or 999 as appropriate).

• Self-refer: you can refer yourself to an NHS talking therapies service without seeing a GP.

The NHS says many people with depression benefit from lifestyle changes such as getting more exercise, cutting down on alcohol, giving up smoking and eating healthily, and that reading a self-help book or joining a support group can also help.

For bipolar disorder, the NHS suggests trying to have a regular routine, getting plenty of sleep, eating a healthy diet, exercising regularly and managing stress, and avoiding recreational drugs, smoking, too much alcohol, shift work or very long hours, flying at night or across time zones if possible, and lots of caffeine. It adds that it is important to know what can trigger your high and low moods, such as stress, not enough sleep or being too busy.

On the NHS you can see a GP or refer yourself directly to an NHS talking therapies service if you are 18 or over (or 16 or over in some areas, according to the NHS SAD page). A GP who suspects bipolar disorder will refer you to a mental health specialist (psychiatrist), who will ask about your moods, behaviour, health and family history; the NHS notes it can take time to diagnose because it affects everyone differently and symptoms are similar to other conditions. Severe depression may be managed by a specialist team.

Private psychiatrists, psychologists and therapists are available for people who want quicker access or a particular type of therapy. The treatments are the same ones described by the NHS, so ask any provider which therapy or medicine they recommend, how progress will be reviewed, and how care will be coordinated with your GP.