 To investigate whether switching to dolutegravir based combination Antiretroviral Therapy cART is associated with resolution of CNS toxicity determined by CNS questionnaire at 12 weeks post switch To investigate continued virological suppression at levels of 400 and 50 copiesml in individuals switching to dolutegravircontaining cART at 4 and 12 weeks post switch To investigate changes in cluster of differentiation 4 CD4 cell count in individuals switching to dolutegravircontaining cART over 12 weeks post switch To investigate the safety laboratory and non CNS adverse events of switching to dolutegravir based cART over 12 weeks post switch To investigate changes in quality of life in individuals switching to dolutegravir based cART as assessed by Quality of life EuroQOL questionnaires over 12 weeks post switch To investigate the impact of switching to dolutegravir based CART on anxiety and depression as determined by Hospital Anxiety and Depression Score HADS over 12 weeks post switch To investigate changes in quality of sleep in individuals switching to dolutegravir based cART as per standardized sleep questionnaire at 4 and 12 weeks post switch To assess the impact of switching to dolutegravir based cART on adherence by standard questionnaire over 12 weeks post switch To investigate changes in neuropsychiatric function in individuals switching to dolutegravir based cART by CogState battery and Instrumental Activities of Daily Life IADL questionnaire over 12 weeks post switch To investigate changes in fasting cholesterol and triglycerides in individuals switching to dolutegravir based cART over 12 weekspost switch To investigate Efavirenz EFV plasma decay and its impact on Dolutegravir DTG concentrations following the switch Maximum Concentration Cmax, Minimum Concentration Cmin, Area Under the concentration-time Curve AUC at weeks 1, 2 and 3 post switch To investigate the association between genetic polymorphisms in drug disposition genes and drug exposure To assess changes in the levels of tryptophan, kynurenine, kynureninetryptophan ratio, neopterin, tumour necrosis factorα and interferonγ in plasma following treatment switch from efavirenz to dolutegravir. 