ADHD

1. ADHD
Dr Amala Musty
Consultant Psychiatrist
Columbus Hospital, Begumpet

2. NEUROBIOLOGY INTRODUCTION
ADHD AS A DISORDER OF
PREFRONTAL CORTEX

3.  ADHD symptoms : Hyperactivity
Inattention
Impulsivity
 All these symptoms hypothesized to arise from
PREFRONTAL CORTEX PATHOLOGY

4.  Attention has 2 components
Focus & Sustain

5.  Deficit in the focus of attention aka selective
inattention
 Is a function of dACC(dorsal anterior cingulate
cortex)
 Is tested by STROOP TEST
 There is absent/deficient activation of dACC in
ADHD pts.

6.  Deficit in sustain attention leads to executive
dysfunction thus inability to solve problems
 Related to DLPFC(dorso lateral prefortal cortex)
 DLPFC activity tested by n-back test
 DLPFC activation is deficient or absent

7.  Executive dysfunction is also found in
Schizophrenia
Mania
Anxiety

8.  Impulsivity
 Linked to Orbitofrontal cortex
 Where impulsivity is seen also seen in
substance abuse
schizophrenia
mania
suicidality

9.  Motor hyperactivity
 Linked to supplemental motor area

10.  ADHD – disorder of inefficient tuning of
prefrontal cortex by dopamine and
norepinephrine