A systematic review and meta-analysis of clinical predictors of lithium response in bipolar disorder.

ABSTRACT

OBJECTIVE: To determine clinical predictors of lithium response in bipolar disorder. METHODS: Systematic review of studies examining clinical predictors of lithium response was conducted. Meta-analyses were performed when ≥2 studies examined the same potential predictor. RESULTS: A total of 71 studies, including over 12 000 patients, identified six predictors of good response mania-depression-interval sequence [odds ratio (OR) 4.27; 95% CI 2.61, 6.97; P < 0.001], absence of rapid cycling (OR for rapid cycling 0.30; 95% CI 0.17, 0.53; P < 0.001), absence of psychotic symptoms (OR for psychotic symptoms 0.52; 95% CI 0.34, 0.79; P = 0.002), family history of bipolar disorder (OR 1.61; 95% CI 1.03, 2.52; P = 0.036), shorter prelithium illness duration [standardised mean difference (SMD) -0.26; 95% CI -0.41, -0.12; P < 0.001] and later age of onset (SMD 0.17; 95% CI 0.02, 0.36; P = 0.029). Additionally, higher body mass index was associated with poor response in two studies (SMD -0.61; 95% CI -0.90, -0.32; P < 0.001). There was weak evidence for number of episodes prior to lithium treatment (SMD -0.42; 95% CI -0.84, -0.01; P = 0.046), number of hospitalisations before lithium (SMD -0.40; 95% CI -0.81, 0.01; P = 0.055) and family history of lithium response (OR 10.28; 95% CI 0.66, 161.26; P = 0.097). CONCLUSIONS: The relative importance of these clinical characteristics should be interpreted with caution because of potential biases and confounding.