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Dr Sagnik Bhattacharyya  MBBS, DPM, Diplomate of National Board (Psychiatry), MD, PhD
Senior Clinical Lecturer & Consultant Psychiatrist

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tel+44 20 7848 0955
fax+44 20 7848 0976
location M6.01.04
Main Wing
departmentsPsychosis Studies


I trained in Medicine and then Psychiatry in India, before coming to the UK to be at the cutting edge of psychiatric research. From obsessive compulsive disorder (I was looking for antibodies to basal ganglia in OCD), I have increasingly become hooked on to Cannabis. As a Consultant Psychiatrist, I work in the early intervention setting.

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activities and interests

Research Activities

The overarching goal of my research into the neurobiology of psychoses is to enable the translation of knowledge into practice, either through the development of novel and better treatments or through the development of preventive strategies, as is widely prevalent in other branches of medicine.

Cannabis Neurobiology: I have focused mainly on Cannabis, which is one of the most robustly implicated environmental risk factors for schizophrenia and arguably the most potentially modifiable risk factor. I have employed the cannabis challenge approach in healthy human volunteers to model psychosis in man, and employed this approach to delineate the risk mechanisms for this environmental risk factor for schizophrenia as well as the genetic factors that moderate vulnerability to its effects.

Funded by a MRC Clinical Research training fellowship, I have carried out studies that elucidated for the first time the neural basis underlying the symptomatic and cognitive effects of cannabis in man (eg. Bhattacharyya et al. Arch Gen Psych 2009; Bhattacharyya et al., Neuropsychopharmacology 2010; Fusar-Poli et al. Arch Gen Psych 2009).

We are currently interested in understanding the neurochemical underpinnings of the symptomatic and neurocognitive effects of cannabinoids in man with a particular focus on brain glutamate and GABA levels. In collaborative work, we are also interested in understanding the molecular underpinnings of the effects of cannabinoids in neurons derived from healthy individuals and patients.

Risk Prediction: My previous work was followed on by a NIHR Clinician Scientist award to extend experimental evidence regarding genetic predictors of sensitivity to the effects of cannabis obtained in healthy people (Bhattacharyya et al., Mol Psych 2012) to patients with psychosis with the aim to identify those who are particularly vulnerable to the effects of ongoing cannabis use, such that personalized treatment approaches can then be developed for those that are most likely to benefit from it.

New treatments: Funded by an Experimental Medicine grant from the MRC, we are attempting to take the next step in translating another of the early findings of my research (Bhattacharyya et al., Neuropsychopharmacology 2010; Bhattacharyya et al., Arch Gen Psychiatry 2012) into a potential new treatment for individuals in the very early stages of psychosis. Currently, there are no safe and effective treatments for this group of young people who have a very high risk of developing a full-blown psychotic disorder.

teaching activities

Module Leader

New module on ’Translational research in Psychiatry’ as part of the MSc in Psychiatric research.

PhD Supervision

I would be pleased to consider applications from those interested in pursuing a PhD.
Please have a look at the links below:

Mental Health Studies » Masters (MSc)
Psychiatric Research » Masters (MSc)
Neuroimaging » Masters (MSc)



1. Bhattacharyya S, Atakan Z, Martin-Santos R, Crippa JA, Kambeitz J, Prata D, et al. Preliminary report of biological basis of sensitivity to the effects of cannabis on psychosis: AKT1 and DAT1 genotype modulates the effects of d-9-tetrahydrocannabinol on midbrain and striatal function. Mol Psychiatry. 2012;17(12):1152-5.
2. Bhattacharyya S, Crippa JA, Allen P, Martin-Santos R, Borgwardt S, Fusar-Poli P, et al. Induction of psychosis by delta-9-tetrahydrocannabinol reflects modulation of prefrontal and striatal function during attentional salience processing. Arch Gen Psychiatry. 2012;69(1):27-36.
3. Bhattacharyya S, Morrison PD, Fusar-Poli P, Martin-Santos R, Borgwardt S, Winton-Brown T, et al. Opposite effects of delta-9-tetrahydrocannabinol and cannabidiol on human brain function and psychopathology. Neuropsychopharmacology. 2010;35(3):764-74.
4. Bhattacharyya S, Fusar-Poli P, Borgwardt S, Martin-Santos R, Nosarti C, O’Carroll C, et al. Modulation of mediotemporal and ventrostriatal function in humans by Delta9-tetrahydrocannabinol: a neural basis for the effects of Cannabis sativa on learning and psychosis. Arch Gen Psychiatry.
5. Fusar-Poli P, Crippa JA, Bhattacharyya S, Borgwardt SJ, Allen P, Martin-Santos R, et al. Distinct effects of {delta}9-tetrahydrocannabinol and cannabidiol on neural activation during emotional processing. Arch Gen Psychiatry. 2009;66(1):95-105.
6. Borgwardt SJ, Allen P, Bhattacharyya S, Fusar-Poli P, Crippa JA, Seal ML, et al. Neural basis of Delta-9-tetrahydrocannabinol and cannabidiol: effects during response inhibition. Biol Psychiatry. 2008;64(11):966-73.6.
7. Bhattacharyya S, Khanna S, Chakrabarty K, Mahadevan A, Christopher R, Shankar SK. Anti-brain autoantibodies and altered excitatory neurotransmitters in obsessive-compulsive disorder. Neuropsychopharmacology. 2009;34(12):2489-96.
8. Chakrabarty K, Bhattacharyya S*, Christopher R, Khanna S. Glutamatergic dysfunction in OCD. Neuropsychopharmacology. 2005;30(9):1735-40.

* Corresponding author

9. Batalla A, Bhattacharyya S, Yücel M, Fusar-Poli P, Crippa JA, Nogué S, et al. Structural and functional imaging studies in chronic cannabis users: a systematic review of adolescent and adult findings. PLoS One. 2013;8(2):e55821.
10. Batalla A, Soriano-Mas C, López-Solà M, Torrens M, Crippa JA, Bhattacharyya S, et al. Modulation of brain structure by catechol-O-methyltransferase Val(158) Met polymorphism in chronic cannabis users. Addict Biol. 2013.
11. Udina M, Foulon H, Valdés M, Bhattacharyya S, Martín-Santos R. Dhat Syndrome: A Systematic Review. Psychosomatics. 2013.
12. Egerton A, Chaddock CA, Winton-Brown TT, Bloomfield MA, Bhattacharyya S, Allen P, et al. Presynaptic Striatal Dopamine Dysfunction in People at Ultra-high Risk for Psychosis: Findings in a Second Cohort. Biol Psychiatry. 2013.
13. Bhattacharyya S, Sendt KV. Neuroimaging evidence for cannabinoid modulation of cognition and affect in man. Front Behav Neurosci. 2012;6:22.
14. Bhattacharyya S, Atakan Z, Martin-Santos R, Crippa JA, McGuire PK. Neural mechanisms for the cannabinoid modulation of cognition and affect in man: a critical review of neuroimaging studies. Curr Pharm Des. 2012;18(32):5045-54.
15. **Kambeitz JP, **Bhattacharyya S, Kambeitz-Ilankovic LM, Valli I, Collier DA, McGuire P. Effect of BDNF val(66)met polymorphism on declarative memory and its neural substrate: a meta-analysis. Neurosci Biobehav Rev. 2012;36(9):2165-77.
** joint first authors.
16. Stone JM, Morrison PD, Brugger S, Nottage J, Bhattacharyya S, Sumich A, et al. Communication breakdown: delta-9 tetrahydrocannabinol effects on pre-speech neural coherence. Mol Psychiatry. 2012;17(6):568-9.
17. Stone JM, Bhattacharyya S, Barker GJ, McGuire PK. Substance use and regional gray matter volume in individuals at high risk of psychosis. Eur Neuropsychopharmacol. 2012;22(2):114-22.
18. Carletti F, Woolley JB, Bhattacharyya S, Perez-Iglesias R, Fusar Poli P, Valmaggia L, et al. Alterations in white matter evident before the onset of psychosis. Schizophr Bull. 2012;38(6):1170-9.
19. Zuardi AW, Crippa JA, Hallak JE, Bhattacharyya S, Atakan Z, Martin-Santos R, et al. A critical review of the antipsychotic effects of cannabidiol: 30 years of a translational investigation. Curr Pharm Des. 2012;18(32):5131-40.
20. Masillo A, Day F, Laing J, Howes O, Fusar-Poli P, Byrne M, et al. Interpersonal sensitivity in the at-risk mental state for psychosis. Psychol Med. 2012;42(9):1835-45.
21. Valli I, Stone J, Mechelli A, Bhattacharyya S, Raffin M, Allen P, et al. Altered medial temporal activation related to local glutamate levels in subjects with prodromal signs of psychosis. Biol Psychiatry. 2011;69(1):97-9.
22. Morrison PD, Nottage J, Stone JM, Bhattacharyya S, Tunstall N, Brenneisen R, et al. Disruption of frontal theta coherence by delta-9-tetrahydrocannabinol is associated with positive psychotic symptoms. Neuropsychopharmacology. 2011;36(4):827-36.
23. Winton-Brown TT, Allen P, Bhattacharrya S, Borgwardt SJ, Fusar-Poli P, Crippa JA, et al. Modulation of auditory and visual processing by delta-9-tetrahydrocannabinol and cannabidiol: an FMRI study. Neuropsychopharmacology. 2011;36(7):1340-8.
24. Crippa JA, Derenusson GN, Ferrari TB, Wichert-Ana L, Duran FL, Martin-Santos R, et al. Neural basis of anxiolytic effects of cannabidiol (CBD) in generalized social anxiety disorder: a preliminary report. J Psychopharmacol. 2011;25(1):121-30.
25. Martín-Santos R, Fagundo AB, Crippa JA, Atakan Z, Bhattacharyya S, Allen P, et al. Neuroimaging in cannabis use: a systematic review of the literature. Psychol Med. 2010;40(3):383-98.
26. Stone JM, Morrison PD, Nottage J, Bhattacharyya S, Feilding A, McGuire PK. Delta-9-tetrahydrocannabinol disruption of time perception and of self-timed actions. Pharmacopsychiatry.
27. Fusar-Poli P, Allen P, Bhattacharyya S, Crippa JA, Mechelli A, Borgwardt S, et al. Modulation of effective connectivity during emotional processing by Delta 9-tetrahydrocannabinol and cannabidiol. Int J Neuropsychopharmacol. 2010;13(4):421-32.
28. Fusar-Poli P, Bhattacharyya S, Allen P, Crippa JA, Borgwardt S, Martin-Santos R, et al. Effect of image analysis software on neurofunctional activation during processing of emotional human faces. Journal of Clinical Neuroscience. 2010;17(3):311-4.
29. Bhattacharyya S, Crippa JA, Martin-Santos R, Winton-Brown T, Fusar-Poli P. Imaging the neural effects of cannabinoids: current status and future opportunities for psychopharmacology. Curr Pharm Des. 2009;15(22):2603-14.
30. Crippa JA, Zuardi AW, Martín-Santos R, Bhattacharyya S, Atakan Z, McGuire P, et al. Cannabis and anxiety: a critical review of the evidence. Hum Psychopharmacol. 2009;24(7):515-31.
31. Bhattacharyya S, Chakraborty K. Glutamatergic dysfunction--newer targets for anti-obsessional drugs. Recent Pat CNS Drug Discov. 2007;2(1):47-55.
32. Fusar-Poli P, Picchioni M, Martinelli V, Bhattacharyya S, Cortesi M, Barale F, et al. Anti-depressive therapies after heart transplantation. Journal of Heart and Lung Transplantation. 2006;25(7):785-93.
33. Bhattacharyya S, Prasanna C, Khanna S, Reddy Y, Sheshadri S. A family genetic study of clinical subtypes of obsessive-compulsive disorder. Psychiatric Genetics. 2005;15(3):175-80.
34. Bhattacharyya S, Reddy YC, Khanna S. Depressive and anxiety disorder comorbidity in obsessive compulsive disorder. Psychopathology. 2005;38(6):315-9.
35. Chakrabarty K, Bhattacharyya S, Christopher R, Khanna S. Glutamatergic dysfunction in OCD. Neuropsychopharmacology. 2005;30(9):1735-40.
36. Bhattacharyya S, Khanna S. Late onset OCD. Aust N Z J Psychiatry. 2004;38(6):477-8.
37. Bhattacharyya S, Girishchandra BG, Khanna S. Early-onset obsessive-compulsive disorder. Can J Psychiatry. 2003;48(5):352-3.
38. Bhattacharyya S, Chaturvedi SK. Metamorphosis of delusion of pregnancy. Can J Psychiatry. 2001;46(6):561-2.

39. Morrison PD, Bhattacharyya S, Murray RM: The Risk of Schizophrenia. In: Pertwee RG, ed. Handbook of Cannabis, Psychopharmacology Handbook Series: Vol 1 (Series Editor: L Iversen), Oxford University Press. (expected in 2013).
40. Bhattacharyya S, McGuire PK: The neural basis for the acute effects of cannabis on learning and psychosis. In: Castle DJ, D’Souza DC, Murray RM, eds. Marijuana and Madness, 2nd edition, Cambridge University Press, 2011.
41. Bhattacharyya S (2007): Immunology of OCD. In: Janardhan Reddy YC, Srinath S, editors. Obsessive Compulsive Disorder- Current understanding and future directions. Bangalore, India: National Institute of Mental Health & Neurosciences, pp 111-135.

42. Bhattacharyya S (2010): The role of neuroimaging in understanding the effects of cannabis on the brain. Encyclopaedia Britannica. (

last updated: Friday, September 06, 2013