Mood Disorders and Schizophrenia

1Two young adults

For two months, Patrick, 24, has lost interest in the football he used to love. He sleeps twelve hours yet wakes exhausted, has stopped eating properly and tells his sister he is "useless to everyone". Aline, 21, in her second year at university, has become convinced that her neighbours are reading her thoughts and that a voice on the radio is commenting on everything she does. She has stopped attending lectures. (Both are illustrative cases.)

Patrick's symptoms suggest a mood disorder; Aline's suggest psychosis, of the kind seen in schizophrenia. Both are serious, both are common worldwide, and both can be treated: with the right care, many people recover fully.

21. Mood disorders

How common? The WHO estimates that 5.2% of adults worldwide experienced depression in 2023, more women (6.2%) than men (4.1%). In the 2018 Rwanda Mental Health Survey, 12.0% of the general population and 35.0% of survivors of the 1994 Genocide against the Tutsi had a current major depressive episode. Bipolar I and II together affect roughly 1% of people over their lifetime (Merikangas and others, 2011).

32. Explaining depression

• Genes. Twin studies suggest that about 37% of the variation in risk of major depression is genetic (Sullivan, Neale and Kendler, 2000). Bipolar disorder is more strongly heritable.
• The brain. For decades depression was popularly explained as a "chemical imbalance" of low serotonin. An umbrella review (Moncrieff and others, 2022) found no consistent evidence for that simple idea. Researchers now study many systems together: stress hormones (an overactive HPA axis, Lesson 3 of Unit 6), inflammation and how brain networks process reward. Antidepressants do help many people: a review of 522 trials (Cipriani and others, 2018) found all 21 antidepressants studied more effective than a placebo for adults with major depression, although the average benefit is modest.
• Cognitive. Aaron Beck (1967) described a negative cognitive triad: negative views of the self ("I am useless"), the world ("everyone is against me") and the future ("it will never get better"), kept going by thinking errors such as overgeneralising. Lyn Abramson, Martin Seligman and John Teasdale (1978) added that people who explain bad events as internal ("my fault"), stable ("always") and global ("in everything") are more vulnerable. Seligman's original "learned helplessness" research gave dogs inescapable electric shocks, which would not be allowed today.
• Social. In a study of women in Camberwell, London, George Brown and Tirril Harris (1978) found that severe life events triggered depression mainly in women who also had vulnerability factors, such as having no one to confide in or losing their mother in childhood: another case of diathesis–stress.

Treatment. Psychological therapies such as CBT, behavioural activation and interpersonal therapy work well. In a randomised trial in rural Uganda, group interpersonal psychotherapy led by trained local facilitators greatly reduced depression (Bolton and others, 2003), showing that effective help need not depend on specialists. Antidepressants are used for moderate and severe depression, often with therapy. Bipolar disorder is treated with mood stabilisers such as lithium, together with psychological support.

43. Suicide: what everyone should know

The WHO reports that more than 720,000 people die by suicide every year and that suicide was the third leading cause of death among 15- to 29-year-olds in 2021. Depression is one of the main risk factors, and suicide is preventable. Asking someone directly and caringly whether they are thinking about suicide does not put the idea into their head; reviews of the research find that it does not increase risk (Dazzi and others, 2014) and may bring relief. Take any mention of suicide seriously, stay with the person, and get help at once from a trusted adult, a health centre or RBC's toll-free number 114.

54. Schizophrenia

About 1 person in 300 worldwide lives with schizophrenia (WHO). It usually begins in late adolescence or early adulthood. Despite a common myth, it does not mean a "split personality"; that confusion comes from the Greek roots of the word ("split mind"), coined by Eugen Bleuler in 1908.

A diagnosis (DSM-5-TR) needs at least two such symptoms for much of a month, including delusions, hallucinations or disorganised speech, with signs of the disturbance lasting at least six months.

65. Explaining schizophrenia

Genes. Family and twin studies show a strong genetic influence (Figure 1). Hundreds of genetic variants each add a tiny amount of risk; there is no single "schizophrenia gene".

Figure 1. Lifetime risk of schizophrenia by relationship to an affected person, from pooled European family and twin studies (Gottesman, 1991). Risk rises with genetic closeness, but even an identical twin, who shares almost all genes, has only about a 48% risk, so genes are not the whole story.

Dopamine. The dopamine hypothesis proposes that too much dopamine activity in certain brain pathways produces positive symptoms. Support: antipsychotic drugs block dopamine D2 receptors, and drugs that boost dopamine, such as amphetamines, can trigger psychosis. Limitations: antipsychotics help negative and cognitive symptoms little, and other neurotransmitters, such as glutamate, are involved. The modern version (Howes and Kapur, 2009) sees dopamine as a "final common pathway" through which many genetic and environmental causes act.

Environment and development. Complications in pregnancy and birth, childhood adversity, growing up in a city, migration and discrimination all raise the risk. So does cannabis: in a study across Europe and Brazil, people who used high-potency cannabis every day had about five times the odds of a psychotic disorder of people who never used it (Di Forti and others, 2019).

Family. In the 1940s some psychiatrists blamed cold, controlling "schizophrenogenic" mothers; this idea has no support and caused families great harm. What does matter is expressed emotion: people returning to families who are very critical or over-involved relapse more often (Vaughn and Leff, 1976), which is why family support programmes are part of treatment.

Treatment. Antipsychotic medication reduces positive symptoms and relapse, but can cause side effects such as weight gain and movement problems, so it is carefully monitored. Family interventions, CBT for psychosis, help with work and education, and early intervention services improve outcomes. The WHO notes that at least one person in three with schizophrenia will be able to recover fully.