Bipolar Disorder in Children and Adolescents: Patient Evaluations - Bipolar Biological and Biochemical Factors

Biological and biochemical factors

• Sleep disturbances often aid in defining abnormal mood states of bipolar disorder in either the manic or depressed state.
  • A profoundly decreased need for sleep in the absence of a sense of fatigue is a strong indicator of a manic state.
  • An uncomfortable reduction of sleep is a pattern of an atypical depression episode in which more sleep is wanted but cannot be achieved. Conversely, a typical depression episode may be indicated by hypersomnolence, an excessive but irresistible need for sleep.
  • The biology that drives these anomalies of sleep in mood disturbances is not fully appreciated. Some suggest that neurochemical and neurobiological shifts cause these episodic sleep disturbances in conjunction with other shifts that occur in the evolution of manic or depressed states.
• Bipolar disorder and other mood disorders are increasingly better understood in the context of neurochemical imbalances within the brain.
  • Although the circuits of the brain that modulate mood, cognition, and behavior are not well defined, the database of neuroimaging studies that facilitate increased appreciation of possible modulating pathways that connect several brain regions to work in unison to regulate thoughts, feelings, and behaviors is constantly growing.
  • An association of neurotransmitters acts upon various brain regions and circuits to modify and regulate brain activity. Table 1 reflects the putative roles of some CNS neurotransmitters within brain circuits.

  Table 1. Neurotransmitters of the CNS

  Neurotransmitter	Activity Modified
  Serotonin	Mood (happy, sad, euthymic)
  Dopamine	Pleasure (hedonia, anhedonia)
  Norepinephrine	Alertness, energy level (lethargy, frenzy, vigilance)
  Acetylcholine	Memory and cognition
  GABA	Inhibition of CNS neurons
  Glutamate	Excitation of CNS neurons

   

  • One proposal suggests that several neurotransmitters acting in unison but with dynamic balance act as modulators of mood states. In particular, serotonin, dopamine, and norepinephrine appear to modify mood, cognition, and sense of pleasure or displeasure.
  • Pharmacotherapy for the regulation of bipolar mood swings is thought to be based on the use of medications that facilitate the regulation of these and perhaps other neurochemicals to restore a normal mood and cognition state.

Sources:

• AACAP Official Action. Practice parameters for the assessment and treatment of children and adolescents with bipolar disorder. J Am Acad Child Adolesc Psychiatry. Jan 1997;36(1):138-57.
• Biederman J, Faraone S, Milberger S, et al. A prospective 4-year follow-up study of attention-deficit hyperactivity and related disorders. Arch Gen Psychiatry. May 1996;53(5):437-46.
• Chang KD, Steiner H, Ketter TA. Psychiatric phenomenology of child and adolescent bipolar offspring. J Am Acad Child Adolesc Psychiatry. Apr 2000;39(4):453-60.
• Faraone SV, Biederman J, Wozniak J, et al. Is comorbidity with ADHD a marker for juvenile-onset mania?. J Am Acad Child Adolesc Psychiatry. Aug 1997;36(8):1046-55.
• Sigurdsson E, Fombonne E, Sayal K, Checkley S. Neurodevelopmental antecedents of early-onset bipolar affective disorder. Br J Psychiatry. Feb 1999;174:121-7.

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