Mood instability, or sudden, unpredictable, and frequent shifts in emotional states, characterizes many types of psychiatric disorder, including attention-deficit/hyperactivity disorder (ADHD), personality disorders, depression, and posttraumatic stress disorder. To say that individuals with bipolar disorder (BD) have mood instability sounds like a tautology. Nonetheless, mood instability has particular relevance to BD: Many patients have irregular or labile moods even when they are between major episodes of mania and depression.1
Children of parents with BD who have high levels of mood instability are at particularly high risk for developing BD (types I or II) in late adolescence or early adulthood.2 The following case provides an illustration:
Dr. David J. Miklowitz
Patrick, age 14, entered treatment with diagnoses of ADHD and other specified bipolar disorder. His mother felt that his behavior resembled that of his father, who had been treated for manic episodes. During the COVID-19 pandemic, Patrick had become increasingly difficult at home, with significant oppositionality, impulsive behavior, and difficulty following through on school assignments or household tasks. His mother’s most significant complaints concerned Patrick’s sudden outbursts of anger and abrupt verbal abuse when she asked him to stop playing video games. When interrupted, he cursed loudly and sometimes turned violent; he had broken a window and a door at home and had on one occasion physically attacked his younger brother. Patrick agreed that he became angry at times, but felt that others provoked him. When queried about depression, he described anxiety and worry. He was unable to describe a particular trigger for his anxiety except for being interrupted in online games with his friends, which made him “feel like a total loser.”
His mother reported that Patrick had multiple 1- to 2-day intervals in which he became “really silly, laughing at nothing,” talking rapidly, jumping from one topic to another, and becoming annoyed when others didn’t share his enthusiasm. In these activated intervals, he slept little and seemed to be full of energy; his mother would hear him talking loudly into his phone throughout the night. During one such interval he had become verbally aggressive with a peer, which had ruined their friendship. Both Patrick and his mother reported that they had been fighting constantly and, in her words, “our house has become a war zone.”
In our recent article in the Journal of the American Academy of Child and Adolescent Psychiatry,3 my coauthors and I examined the association between parents’ ratings of mood instability and clinicians’ longitudinal ratings of symptoms and functioning among youth (ages 9-17 years) who were at high risk for BD. The participants met DSM-5 diagnostic criteria for major depressive disorder or other specified BD, defined as recurrent and brief periods of elevation and activation that did not meet syndromal mania or hypomania criteria. All participants had at least one first- or second-degree family member with a history of BD I or II. Following a period of evaluation, participants were randomly assigned to one of two 4-month psychological therapies: Family-focused therapy (12 sessions of psychoeducation, communication training, and problem-solving skills training) or enhanced usual care (6 sessions of family and individual psychoeducation and support). They also received pharmacological management from study-affiliated psychiatrists when warranted.
We measured mood instability at intake and every 4-6 months over an average of 2 years (range 0-255 weeks). We used a brief parent questionnaire – the Children’s Affective Lability Scale4 – which enables measurement of lability on the dimensions of elevation or activation (e.g., bursts of silliness or hilarity, excessive familiarity with others), irritability (e.g., temper outbursts), or anxious-depression (e.g., sudden bouts of crying).