Substance use in bipolar disorder : associations with age at onset, treatment delay and outcome
Appears in the following Collection
- Psykologisk institutt 
AbstractThe overall aim of this thesis was to investigate the relationship between substance use and central aspects of bipolar disorder (BD); the development or onset of the disorder, the clinical and functional characteristics, and the initiation of adequate treatment.
The prevalence of substance use disorders (abuse or dependence) among patients with BD are generally high, but also vary widely. Furthermore, to what degree and in which outcome areas substance use disorders have a negative impact on the BD is still unclear, and little is known about the role of excessive substance use that does not meet diagnostic criteria. Thus, the first aim was to investigate lifetime rates of illicit substance use in BD relative to the normal population, and if there are differences in clinical and functional features between BD patients with and without excessive substance use. The rate of lifetime illicit substance use was found to be significantly higher among the 125 BD patients compared to the 327 persons randomly drawn from the population. BD patients with excessive substance use (45% of total) had poorer educational level, occupational status, GAF-scores and medication compliance, with a trend towards higher suicidality rates, compared to patients without. There were no significant differences between BD patients with or without excessive substance use in current symptom levels or disease course. Recently, there has been increasing focus on the age at onset of BD. Variation in age at onset has been associated with several factors, including substance abuse. However, the relationship between age at onset, type of substance use and sequencing of the onsets of BD and excessive substance use calls for further investigation. The second aim was to investigate which factors are associated with age at onset in BD with a specific focus on excessive alcohol and cannabis use, and the sequence of the onsets of excessive substance use and BD. Among the 151 BD patients investigated, patients with excessive alcohol use had a significantly later onset compared to patients with excessive cannabis use. Excessive general substance use prior to BD onset was associated with a later onset. Excessive cannabis use was associated with an earlier onset whether it preceded or followed BD onset, also after adjusting for possible confounders such as a family history of psychotic/affective disorders or use of alcohol or other illicit substances.
Research has shown that the delay between the onset of BD and adequate treatment is long. How this delay is related to excessive substance use is sparsely investigated, but previous research indicates that it may both delay and expedite treatment initiation. When patients experience long delays from onset of the BD until treatment initiation, this may also increase the risk of excessive substance use as an attempt to self-medicate increasing symptoms. The third aim was to investigate whether excessive substance use before illness onset is associated with increased or reduced treatment delay, and whether long treatment delays are associated with increased risk for subsequent excessive substance use. Among the 151 BD patients investigated, the risk of a long treatment delay (>2 years from first elevated episode to adequate pharmacological treatment) was reduced when excessive substance use was present before the onset of the BD. In patients with no excessive substance use prior to the onset of the BD, the risk for subsequently developing excessive substance use was increased with longer treatment delays after controling for possible confounders such as gender and educational level. The conclusions of the current thesis were that patients with BD are at greater risk for lifetime use of illicit substances than the normal population and that BD patients with excessive substance use clearly have impaired functioning, but not a worse course of illness compared to patients without excessive substance use. Furthermore, finding that alcohol use was associated with a later onset compared to cannabis use suggests different relationships between these substances and the onset of BD. The association between excessive cannabis use and an earlier BD onset indicates that an early onset may increase the risk of cannabis use and that cannabis use may trigger BD in vulnerable individuals. Lastly, since excessive substance prior to BD onset was associated with a reduced risk for long treatment delays, it does not appear to be an obstacle for initiating treatment for BD. The finding that the risk for developing excessive substance use after BD onset increased with longer treatment delays is in line with the self-medication hypothesis.
List of papers
(paper III is removed due to copyright restrictions) Paper I: Lagerberg, T.V., Andreassen, O.A., Ringen, P.A., Berg, A.O., Larsson, S., Agartz, I, Sundet, K., Melle, I. Excessive substance use in bipolar disorder is associated with impaired functioning rather than clinical characteristics, a descriptive study. BMC Psychiatry 2010, 10:9. DOI 10.1186/1471-244X-10-9
Paper II: Lagerberg, T.V., Sundet, K., Aminoff, S., Berg, A.O., Ringen, P.A., Andreassen, O.A., Melle, I. Excessive cannabis use is associated with earlier age at onset compared to excessive alcohol use in bipolar disorder. Accepted with minor revisions in European Archives of Psychiatry and Clinical Neuroscience. DOI 10.1007/s00406-011-0188-4
Paper III: Lagerberg, T.V., Larsson, S., Sundet, K., Hansen, C.F., Hellvin, T., Andreassen, O.A., Melle, I. Treatment delay and excessive substance use in Bipolar Disorder. J of Nerv Ment Dis 2010 Sep;198(9):628-33. DOI 10.1097/NMD.0b013e3181ef3ef4