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Thesis summary
Outside of family history, few risk factors for bipolar disorder have been identified. Cannabis use is common in bipolar disorder and there is evidence that cannabis use can affect illness severity. There are still few reports on cannabis use in first episode bipolar disorder. The aim of the thesis was to assess the influence of cannabis before and after onset of bipolar disorder in terms of age at onset, symptoms at first episode, symptoms one year after first treatment and how cannabis influences treatment delay. Information was obtained by performing semi-structured interviews, reviewing medical records, and using self-report questionnaires.
Use of cannabis within the last six months before onset was associated with earlier age at onset for both manic and psychotic episodes. Recent use was also associated with higher prevalence of lifetime suicide attempts. Furthermore, continued cannabis use after the first episode was associated with both elevated mood and poorer global functioning, where the elevated mood mediated the effect of cannabis use on global functioning. While the length of treatment delay did not influence the amount or severity of symptoms at first treatment episode, there was an association between increased risks of excessive cannabis use for patients with longer duration of untreated manic episodes after illness onset.
Overall, the results of this study support that both premorbid and continued cannabis use, also below the threshold of a diagnosis of abuse or dependency is of clinical significance in recent onset bipolar disorder.
Scientific papers included in the thesis
Kvitland LR, Ringen PA, Aminoff SR, Demmo C, Hellvin T, Lagerberg TV, Andreassen OA, Melle I. Duration of untreated illness in first-treatment bipolar I disorder in relation to clinical outcome and cannabis use. Psychiatry Res. 2016 Dec 30;246:762-768. doi: 10.1016/j.psychres.2016.07.064.
Kvitland LR, Melle I, Aminoff SR, Demmo C, Lagerberg TV, Andreassen OA, Ringen PA. Continued cannabis use at one year follow up is associated with elevated mood and lower global functioning in bipolar I disorder. BMC Psychiatry. 2015 Feb 5;15:11. doi: 10.1186/s12888-015-0389-x.
Kvitland LR, Melle I, Aminoff SR, Lagerberg TV, Andreassen OA, Ringen PA. Cannabis use in first-treatment bipolar I disorder: relations to clinical characteristics. Early Interv Psychiatry. 2016 Feb;10(1):36-44. doi: 10.1111/eip.12138.