Glossary

Disorders

Personality Disorder(s) (PD(s)):
A group of disorders involving the self (identity, self-worth etc), affecting relationships, cognition, emotions and behaviours.
Here are the DSM-5-TR Personality Disorder criteria & ICD-11 criteria.
Antisocial Personality Disorder (AsPD):
A PD involving "a pattern of disregard for, and violation of, the rights of others, criminality, impulsivity, and a failure to learn from experience".
Avoidant Personality Disorder (AvPD):
A PD involving "a pattern of social inhibition, feelings of inadequacy, and hypersensitivity to negative evaluation".
Borderline Personality Disorder (BPD):
A PD involving "a pattern of instability in interpersonal relationships, self-image, and affects, and marked impulsivity".
Dependent Personality Disorder (DPD):
A PD involving "a pattern of submissive and clinging behavior related to an excessive need to be taken care of".
Histrionic Personality Disorder (HPD):
A PD involving "a pattern of excessive emotionality and attention seeking".
Narcissistic Personality Disorder (NPD):
A PD involving "a pattern of grandiosity, need for admiration, and lack of empathy".
Obsessive-Compulsive Personality Disorder (OCPD):
A PD involving "a pattern of preoccupation with orderliness, perfectionism, and control".
Paranoid Personality Disorder (PPD):
A PD involving "a pattern of distrust and suspiciousness such that others’ motives are interpreted as malevolent."
Schizotypal Personality Disorder (StPD):
A PD involving "a pattern of acute discomfort in close relationships, cognitive or perceptual distortions, and eccentricities of behavior".
Schisoid Personality Disorder (SzPD):
A PD involving "a pattern of detachment from social relationships and a restricted range of emotional expression".
Dissociative Identity Disorder (DID):
A dissociative disorder characterised by two or more personality states who can take control of the person's body. Accompanying these personality switches is amnesia.
Other Specified Dissociative Disorder (OSDD):
A diagnosis for presentations which don't match other dissociative disorders.
OSDD 1
A category for sub-clinical DID. Someone with OSDD 1 may have alternate personalities but no amnesia, or amnesia with personality states that aren't distinct or separate.
Depersonalisation / Derealisation Disorder (DPDR):
A dissociative disorder involving chronic dissociation. Depersonalisation is feeling a disconnection between you and your body, memories, emotions, and/or sensations. Derealisation is a disconnect between you and your environment or reality.
Dissociative Amnesia (DA):
Amnesia, not caused by another condition, that goes beyond ordinary forgetting. Usually the amnesia is for traumatic events.
Post Traumatic Stress Disorder (PTSD):
A disorder resulting from exposure to a traumatic event(s). Symptoms include intrusive symptoms (such as nightmares, flashbacks, distress at reminders of trauma); avoidance of reminders of trauma (such as memories or similar places); emotional or cognitive symptoms (such as amnesia for the trauma, depression, persistent guilt or shame); and changes in reactivity (such as hypervigilance, irritability, sleep problems).
Complex PTSD (C-PTSD):
A disorder resulting from exposure to long-term, complex traumatic events. The symptoms are the same as PTSD, plus problems with emotions (such as recklessness, aggression, dissociation, constantly feeling numb), low self-esteem and self-worth and "deep and pervasive feelings of shame, guilt or failure", & relationship problems.
Attention Deficit Hyperactive Disorder (ADHD):
A neurodevelopmental disorder involving difficulties with attention, hyperactivity and impulsivity.
Autism Spectrum Disorder (ASD):
A neurodevelopmental disorder involving restricted, repetitive interests, behaviours and activities, and difficulties with communication and social interaction.
Paraphilic Disorders
A group of disorders involving intense and persistent sexual interests that cause distress and impairment to either the person or others.

Other terms

CSA:
Child sexual abuse.
Cluster A:
A grouping of "odd or eccentric" PDs, including PPD, SzPD, & StPD
Cluster B:
A grouping of "dramatic, emotional, or erratic" PDs, including AsPD, BPD, NPD & HPD
Cluster C:
A grouping of "anxious or fearful" PDs, including AvPD, DPD, & OCPD
Dissociation
Essentially, a feeling of disconnection. There are five types of dissociation: depersonalisation, derealisation, dissociative amnesia, identity confusion, and identity alteration. Identity confusion is feeling unsure about who you are, which goes beyond normal, healthy questioning of identity. Identity alteration is only experienced in DID and OSDD 1 and is caused by alters switching.
Alter(s):
Also called parts, alternate personalities or personality states, self states, identities or identity states, and ego states, as well as many other names. These are parts of the self that have become separated due to childhood trauma. They can range from fragments, which are alters that don’t have a strong sense of separation or differentiation, to fully formed alters, which often do feel strongly separated and differentiated. When one alter stops being in control of the body and another alter steps in, this is called switching.
Psychosis
A group of symptoms involving detachment from shared reality, such as delusions (persistent false beliefs) and hallucinations (sensory input that isn't actually happening), disorganised speech / thinking, strange behaviour, experiences of loss of control, and negative symptoms such as lack of speech, lack of interest in activities, and lack of motivation.
The Diagnostic and Statistical Manual (DSM):
The Diagnostic and Statistical Manual of Mental Disorders is a manual for clinicans published in the United States, for diagnosing mental disorders. It's currently in it's fifth edition and has recently been revised. Here is a PDF of DSM-5-TR.
International Classification of Diseases (ICD):
The International Classification of Diseases is a categorisation system published by the World Health Organisation, which lists 17,000 diagnostic categories, with over 100,000 medical diagnoses. It's not limited to mental disorders like the DSM. It's currently in it's eleventh revision. It's freely available online.
Psychodynamic Diagnostic Manual (PDM):
The Psychodynamic Diagnostic Manual is a diagnostic manual of mental disorders, which looks at mental disorders from a multidimensional model instead of in isolation, like the ICD and DSM tend to. It's currently in it's second edition. Here is a PDF of the PDM-2.